Flowey

Flowey (/ˈflaʊ.iː/, Flaowee ) is the first major character that the protagonist encounters in Undertale. He provides an introduction to the mechanics of encounters by sharing "friendliness pellets", which are harmful bullets. He attempts to kill the protagonist and imparts his philosophy of "kill or BE killed" while his bullets encircle the protagonist's SOUL. In the Genocide Route, he reveals that he was attempting to steal the protagonist's SOUL. He is the main antagonist of both the Neutral and Pacifist routes.

Appearance
Flowey usually appears as a sentient, grinning, golden flower, with a white androecium, six yellow petals, and a green stem. Flowey can dramatically contort his face into a variety of expressions and mimic the faces and voices of other characters. He mimics Toriel and Asgore in some situations, and he also imitates his old self at the end of the Genocide Route.

Personality
Initially, Flowey operates under a facade of friendliness and politeness. He often greets the protagonist with "Howdy!", calls himself "your best friend", and, like his father, appends polite words such as "gosh" and "golly" to the ends of his sentences. Whenever he drops this guise of friendliness, he often calls the protagonist an "idiot." His central philosophy is that "In this world, it's kill or be killed."

Flowey has a malevolent disposition, and he berates the protagonist for not following his philosophy. However, he also criticizes the protagonist at the end of the Ruins if they killed any monster. He reminds the protagonist that "Someone is dead because of you." He is a cunning planner and subtle if the circumstances require it; he manipulates the protagonist into befriending all monsters in a True Pacifist run and uses this friendship to his advantage. He is able to retain his memories between SAVEs (having once had the ability to do so himself.) He also possesses a disturbing sense of humor, as shown in his boss fight, in which he turns into "Photoshop Flowey," or "Omega Flowey" as dubbed by fans.

Ruins Start
When starting the game for the first time or after a True Reset, Flowey will first appear at the start of the game to provide a tutorial of sorts. He urges the protagonist to run into his "friendliness pellets." However, if the protagonist runs into these "pellets," which are bullets, Flowey announces his "kill or be killed" attitude to the protagonist. If the protagonist kills Flowey on a previous Neutral playthrough, he will not appear at all. If the protagonist leaves them alive, he reminds the protagonist not to kill anyone. If the protagonist does not kill anyone, Flowey reminds them to befriend everyone because if they do not, they'll be "miserable forever."
 * The protagonist can dodge his bullets up to three times, which causes his act to slip gradually until he hypocritically snaps at the protagonist for toying with him.
 * The background music lowers by one semitone each time the bullets are dodged, before slowing, lowering pitch, and stopping entirely.
 * Before making his third attack, Flowey will accidentally scream "RUN. INTO. THE. BULLETS!!!" before quickly changing the "BULLETS!!!" in the speech bubble to "friendliness pellets".
 * Pressing Z to try to skip through the dialogue will cause the speech bubble to go blank; mashing Z very rapidly will cause Flowey to say simply "stop it."
 * Either way, Flowey will then proceed to surround the protagonist in an inescapable ring of bullets which close in on the protagonist. However, this attack is prevented by the timely arrival of Toriel.

Ruins End
At the exit to the Ruins, Flowey reappears to judge the protagonist's actions up to that point.
 * If the protagonist spared Toriel, Flowey calls them "clever", but reminds them that they only spared a single person's life:
 * If the protagonist has killed any other monster, he lists the names of every killable monster in the Ruins and points out that every one of them may have had families and loved ones, regardless of which enemy types the protagonist has killed or how many they have killed. He calls the protagonist a selfish brat and says: "Somebody is dead because of you."
 * If the protagonist did not kill anybody and had never killed Toriel, Flowey speculates that if they meet a "relentless killer," they will repeatedly be killed until they eventually give up. Flowey wonders if they will either kill out of frustration or quit the game entirely, leaving control over the world (through the ability to SAVE, though this is not stated) to Flowey. He tells the protagonist that he will not kill them, and instead will watch them struggle through the rest of the Underground.
 * If the protagonist had killed Toriel at least once before, then reset or loaded the game to spare her, Flowey tells them not to get cocky and proceeds to taunt them by pointing out what they had done: "You murdered her. And then you went back, because you regretted it". He informs the protagonist he previously had the power to SAVE and reset, and that he played as the world's god before the protagonist's arrival superseded his (this is later accredited to the protagonist's Determination). He tells the protagonist that he will be watching them.
 * If the protagonist killed Toriel:
 * If the protagonist killed Toriel once and hadn't gotten past her before that point, Flowey mocks Toriel for trying to save the protagonist when she ultimately couldn't save herself.
 * If the protagonist kills Toriel, reloads the game, and then kills her again, Flowey calls the protagonist a "disgusting animal" for not even trying to spare her.
 * Repeated murder will have him question how many times the protagonist will continue to do this.
 * If the protagonist had spared Toriel once before, then killed her, Flowey calls them "utterly repulsive." He remembers the protagonist had spared her life, then goes on to taunt them, saying they went back and murdered her just to see what would happen. He informs the protagonist he previously had the power to SAVE and reset, and that he played as the world's god before the protagonist's arrival superseded his. He tells the protagonist that he will be watching them.
 * If the protagonist has met the requirements to begin the Genocide Route, Flowey questions if they are human. He sees a kindred spirit inside them - Chara. He tells them of his "wonderful idea" to become all powerful and destroy everything in the world together.
 * If the protagonist skips Toriel fight via debug mode or a similar method, Flowey will simply say "error" every time the protagonist attempts to talk to him, as an outcome of the Toriel fight has not occurred.
 * If the protagonist has killed him in a Neutral Route and then performs a normal reset, Flowey will not appear at all.

Neutral Route
After the Ruins, Flowey will be seemingly absent from the remainder of the game until the end of the encounter with Asgore. However, there are several moments throughout the game where if the protagonist backtracks, Flowey can be seen at the edge of the screen, before he rapidly disappears into the ground.

If the protagonist decides to backtrack around a vertical room with several Echo Flowers and a sign about the "fallen angel" in Waterfall, he will leave a message to the echo flower closest to him. He will either taunt the protagonist about how Toriel will forget about them and find another child to take care of, or remind the protagonist about how she is trapped in a cold, dark void with nobody to rescue her depending on whether the protagonist has killed her or not.

At the end of the fight with Asgore, if the protagonist decides to kill Asgore, Flowey will appear and absorb the six bottled human souls. If Asgore is spared, Flowey will appear nevertheless, and kill Asgore himself.

After this occurs, the game will suddenly close. Upon relaunching the game, the intro seems to play as normal. However, the Boss Monster is replaced with a Loox, and the intro cannot be skipped. Suddenly, the text "One day, war broke out between the races" will be replaced with "One day, they all disappeared without a trace", as well as the two figures being changed. The screen seems to glitch, and the title of the window rapidly changes between random sets of letters.

Flowey's SAVE file entitled "My World" will show up, which has the LV as 9999 and play time as 9999:99, and the game window will now be titled "Floweytale". Selecting Restart does not work, so "continuing" the game is the only possibility. The protagonist will be plunged into a black void. If the protagonist continues upward, they will find a SAVE point containing their last SAVE.

After this SAVE file is opened, Flowey will appear, destroy it, and gloat, stating that because of the protagonist's idiocy, Asgore is dead, and Flowey now possesses the six human souls. He states that once he absorbs his seventh SOUL—the protagonist's—he "will become God," and he will teach monsters, humans, and everyone else the "real meaning of this world": kill or be killed.

After this, an encounter with Photoshop Flowey occurs. This battle is not RPG-oriented; instead, it is entirely a bullet-hell encounter. As the fight progresses, the protagonist manages to call for help from each of the six souls. After doing so, the souls reduce Flowey's defense to zero, which allows the protagonist repetitively attack Photoshop Flowey until Flowey's health drops to zero. After doing so, Flowey will reload the save file to an alternative slot, and gloat about their power. He then will repetitively kill the protagonist, and reload, before finally deciding to save over their death. However, before Photoshop Flowey manages to do this, the souls manage to revolt against Photoshop Flowey and defeat him by removing his power to reset and control the timeline.

After this, one of the Neutral endings will occur. Then, Flowey will reappear, and advise the protagonist on how to get a better ending. If the protagonist had gone through the game killing enemies, Flowey, believing his "kill or be killed" philosophy may be meaningless, will ask the protagonist to prove it to him by playing the game again without killing anyone. He then promises not to kill the king and will give the protagonist their "happy ending." If the player then resets the game, Flowey will remind them to make friends with everyone, skipping the tutorial "fight", and Flowey's post-Toriel dialogue entirely.

If the protagonist had spared every single enemy, yet they have not met all the requirements for the True Pacifist Route, he mentions that maybe the protagonist could get closer to Papyrus, Undyne, or Alphys depending on whether or not the protagonist had completed their side quests to become friends. Flowey then allows the protagonist to recover their previous save file and follow his advice.

If the protagonist kills Flowey, he will acknowledge the protagonist successfully finishing him off, before seemingly becoming a regular flower. Before this, a rare bug may occur in which the screen will crash at the dead Flowey, with an empty dialogue box. When the game is re-opened, nothing is left but the regular flower.

Flowey will not leave a message for the protagonist after the credits close, and after a reset will not appear at all until after the fight with Asgore, where Flowey will berate the protagonist for thinking that killing him solved anything. He explains that he was brought back when the protagonist loaded their SAVE file and that they still cannot achieve their happy ending. He then destroys Asgore's soul.

This time around, the protagonist is not able to fight Flowey, as he has knowledge that the SOULs would rebel, and fighting the protagonist would be useless. Afterward, the protagonist is left in the same room they would be left in had they just fought Flowey, and leaving the room just leads to Sans's phone call.

If the protagonist has come near to completing a Genocide Route but reset after killing Sans, Flowey will state "We came so close to TRUE victory there!" and says the protagonist will eventually return to their malicious ways.

In Battle
Notably, Flowey in his regular flower form does not have an actual fight where the protagonist can fight back.

Attacks
In his regular form as a mere flower, Flowey uses only two attacks, consisting of a five-bullet spread that slightly hone in on the protagonist's SOUL, and a large ring of bullets which surround the SOUL and cannot be dodged. He can speed up the spread though the limits of his attacks and speed are unknown. Getting hit by his five-bullet spread reduces HP to 1.

Trivia

 * Along with Mettaton, Flowey is one of the only characters in the game to have a voice clip. Near the beginning of the Genocide Route, he exclaims "that's a wonderful idea!".
 * Flowey saying "That's a wonderful idea!" is a higher-pitched clip of an old McDonald's commercial originating from the 1960's as seen in this video by Adam Powell.
 * There are other clips within the commercial which have the same, if not exact, voice and sound clips. Examples are times 2:47 and 3:05, where Photoshop Flowey's "hurt" sounds originate.
 * If "Flowey" is inputted for the fallen child's name, the response becomes "I already CHOSE that name" and prevents the name from being used.
 * While exploring the True Laboratory, the protagonist encounters a strange machine whose form eerily resembles that of Photoshop Flowey, albeit hollow and without Flowey's extra teeth, gums, or eyes. This is the DT Extraction Machine, which Alphys used to extract determination from the six previously captured human SOULs, the same SOULs that Photoshop Flowey would use to power himself.
 * In a joke thread on Starmen.Net, when Undertale was called "UnderBound 2," it was revealed that Flowey was planned to be the reincarnation of "Face" who was the protagonist of the non-existent EarthBound hack, UnderGround.
 * Flowey's laugh is not an entirely new asset and can be recognized in other media such as the PlayStation title Tomba! and the soundtrack "The Lordling" also by Toby Fox. The full, unedited laugh can be heard here.
 * At the end of the demo, Flowey's face disappears from the flower in the first image in the "Instructions" folder. In addition to this, the final image will change to a note that reads: "A Note From Your Friend - Don't get too cocky."
 * However, if this is a genocide run, the first image in the "Instructions" folder will remain the same as it was when the game was started. All the other images will be replaced with the demo's Genocide Route ending screen, and the last image will be replaced with a faceless Flowey.
 * Flowey's character might be inspired by flowers from EarthBound.
 * If the game is reset during a Genocide Route, Flowey says "Really, [name]? Well, do what you will. I'll be waiting for you", implying some disappointment or sense of betrayal. Additionally, this will skip the tutorial "fight", and Flowey's post-Toriel dialogue entirely.
 * If a Neutral Route is completed after aborting the Genocide Route, Flowey will scold the protagonist about quitting before achieving true victory, before realizing that perhaps the protagonist wanted to see everything the underground had to offer before they destroyed it.
 * After resetting a neutral run, or if the game is closed during the initial event with Flowey, and then reopened, Flowey's dialogue will slightly differ. He will question if introducing himself was necessary, implying that the protagonist already knew about him, and will proceed to teach them "proper manners" and start the tutorial. Doing this again will cause Flowey to say "Don't you have anything better to do?" before starting the tutorial, which will loop if the game is restarted again.
 * If the protagonist has already fought Flowey in a timeline, fighting him again is impossible. Attempting to fight him again will make Flowey remark that the six human souls would probably revolt again. Trying to fight him a second time will have him ask the protagonist if they have "anything better to do." Attempting to fight Flowey any more times will leave him speechless.
 * When some certain monsters are attacked, the same sound effect when Flowey is interrupted by Toriel at the beginning of the game will play.
 * If one restarts their game after a successful neutral run while killing a single monster or more, Flowey will remind the protagonist that they have to not kill anyone. He will then disappear, leaving Toriel to come down and find the protagonist. When loading subsequent times, Flowey will not show up at all.
 * Flowey has the most talking sprites out of any character in the game.
 * If the player backtracks during certain rooms of the game after meeting Flowey, they might be able to see him sinking into the ground behind them. This implies that Flowey stalks the protagonist throughout their journey underground.
 * If the protagonist resets the game when almost completing a True Pacifist Route, Flowey will tell the protagonist that they must become friends with everyone, or else they'll be miserable forever.