Mad Dummy

The Mad Dummy is a monster that is a dummy that has been possessed by a ghost in the Underground. The Mad Dummy takes the appearance of a dummy with a set of upper teeth on the torso, a set of eyes on the head, and nostrils on the nose. The Mad Dummy is shown to have a vengeful and aggressive personality, getting in the way of the player.

Pacifist/Neutral Route
When the Mad Dummy is encountered in the Garbage Dump in Waterfall, it reveals that the first dummy that you talked to was possessed by this dummy's cousin. No matter how you interacted with the first dummy, the Mad Dummy will be enraged by how you dealt with their cousin. It attacks the player with the intentions of stealing their soul. In battle, the Fight command misses, the ACT commands do not impact the battle, and the opponent cannot be spared. As such, to defeat the Mad Dummy, the player must maneuver around the enemy's bullets so that they hit it instead of themselves. Once you last long enough, the battle will eventually be topped by Napstablook's arrival.

Genocide Route
When encountering the Mad Dummy in the Genocide Route, the amount of hatred directed towards the player's actions allowed it to 'fuse with its body', fulfilling its lifelong wish. As a reward, it's willing to spare you as soon as combat begins. Unfortunately for the newly-renamed Glad Dummy, it's now vulnerable to physical attacks, and a dedicated player kills it in one shot.

Attacks

 * Mad Dummy calls for help of other dummies. They either summon fuzzy scribbles, that if dodged, can hit and damage Mad Dummy, or flash red and fall in the opposite direction they appear.
 * After a while, he fires the old Dummies and call in robotic ones. They summon rockets that follow the player's SOUL, and go in a straight line after their pink circle runs out. Those rockets can also damage Mad Dummy.
 * Right before the end of the fight, Mad Dummy will throw a single knife at you. This is easily avoided, and only happens once.

Strategy
In a Pacifist Run, ACTing has no result and this enemy cannot be spared. In order to continue the Pacifist run, the player must dodge Mad Dummy's attacks, while slightly aiming the attacks to hit it.

However the part with Dummy Bots is turn-based. Regardless of his attacks hitting him or not, the battle will end after a few turns.

Quotes

 * Futile. Futile! FUTILE! [Neutral]
 * Pitiful. Pitiful! PITIFUL! [Neutral]
 * Foolish. Foolish! FOOLISH! [Neutral]
 * (Wait, is dummy a compliment?) [Neutral]
 * OWWWW, you DUMMIES!! Watch where you're aiming your MAGIC attacks! ... Hey! You! Forget I said anything about MAGIC!!! [Neutral]
 * I'll defeat you and take your SOUL!! [Neutral]
 * I'll use your soul to cross the barrier! [Neutral]
 * I'll stand in the window of a fancy store! [Neutral]
 * THEN EVERYTHING I WANT WILL BE MINE! [Neutral]
 * Huh? Yeah, I guess then I'll avenge my cousin. [Neutral]
 * What was their name again...? [Neutral]
 * Whatever. Whatever! WHATEVER! [Neutral]
 * HEY GUYS! Dummies. Dummies! DUMMIES! Remember how I said NOT to shoot at me? Well... FAILURES! YOU'RE FIRED! YOU'RE ALL BEING REPLACED!!! Hahaha. Hahaha! HAHAHA! Now you'll see my true power: Relying on people that aren't garbage! [Neutral]
 * DUMMY BOTS! MAGIC MISSILE! [Neutral]
 * DUMMY BOTS! TRY AGAIN! [Neutral]
 * DUMMY BOTS! You're awful??? [Neutral]
 * DUMMY BOTS! FINAL ATTACK! [Neutral]
 * (N... no way! These guys are even WORSE than the other guys!) Who cares. Who cares! WHO CARES!! I DON'T NEED FRIENDS!!! I'VE GOT KNIVES!!! [Neutral]
 * I'm... Out of knives. BUT IT DOESN'T MATTER!!! YOU CAN'T HURT ME AND I CAN'T HURT YOU! YOU'LL BE STUCK FIGHTING ME... Forever. Forever! FOREVER!!!! [Neutral]
 * AHAHAHAHAHHAHAHAHAHAHAHAHAHAHAHAH [Neutral]
 * Wh... What the heck is this!? Ergh! Acid rain!?! Oh, FORGET IT! I'm outta here! [Neutral]
 * Foolish. Foolish! FOOLISH! Even if you attack my vessel, you'll NEVER hurt me! I'm still incorporeal, you DUMMY!!! [Attack]

Flavor Text

 * Because they're a ghost, physical attacks will fail. [Check]
 * Mad Dummy blocks the way! [Neutral]
 * Mad Dummy is looking nervous. [Neutral]
 * Mad Dummy is doing an armless ska dance. [Neutral]
 * Mad Dummy glares into a mirror, then turns to you with the same expression. [Neutral]
 * Mad Dummy is bossing around its bullets. [Neutral]
 * Mad Dummy is getting cotton all over the dialogue box. [Neutral]
 * Mechanical whirrs fill the room. [Neutral]
 * Smells like a clothing store. [Neutral]
 * You talk to the DUMMY. ... It doesn't seem much for conversation. No one is happy with this. [Talk]

Trivia

 * Mad Dummy several possible references to JoJo's Bizarre Adventure: Stardust Crusaders.
 * He yells out "Foolish. Foolish! FOOLISH!", "Futile. Futile! FUTILE!", and "Pitiful. Pitiful! PITIFUL!" similar to how DIO would repeatedly yell out "MUDA! MUDA! MUDA!". He also pulls out a knife which has been alluded to how DIO pulls out and throws a multitudes of knives.
 * In addition to this, the Mad Dummy is later seen outside of Undyne's house, taking a job as a punching bag. This arrangement may be another reference to DIO and his Stand, The World, as both are adorn with green hearts while Undyne can turn the player's soul green.
 * His theme is a remix of Napstablook's theme, presumably because he is just a ghost possessing a Dummy, and is entitled "Dummy".
 * It's stated that Napstablook's cousin also went to possess a training dummy, though it is unknown if either Mad Dummy or his cousin are related to them at all.