In order to encounter Glyde, the protagonist must go to the Mysterious Door room outside Snowdin (with the four mushrooms), and move for at least three minutes. This encounter must happen before the fight with Papyrus if the protagonist didn't kill any monster in Snowdin, or Glyde does not appear. Glyde would also disappear during any route after the date with Papyrus. The higher the kill count of the protagonist during the Genocide Route, the longer it takes for Glyde to appear — at most thirty minutes.
Glyde is shown to be very pretentious and rude, doing anything to get the protagonist's attention and even getting jealous of itself at times.
- Waves of star-shaped bullets are sent towards the protagonist, similar to the final boss of the Neutral Route.
- Same as before, but larger, exploding versions of star-shaped bullets accompany it in-between waves, making it harder to dodge.
- Rarely, Glyde says one of its lines as if about to perform a normal attack, but then no projectiles appear.
- To spare them, the protagonist must applaud them twice and then do "nothing" for the rest of the battle.
- ... [Neutral]
- How great I am. [Neutral]
- Look. Watch. Observe. [Neutral]
- Sorry... for NOTHING *ollies* [Neutral]
- Wow. Check out my pecs. [After Applaud x1]
- Ok! I rule. I admit it! [Applaud]
- What else do you have to say? [Applaud x2 onward]
- Boo? What a wimpy ghost. [Boo]
- Mmm, Fresh Sweet Haters. [Boo #2]
- Eh? You forgot to clap. [Nothing]
- HELLO?? I'M RIGHT HERE!!! [Nothing #2]
- Refuses to give more details about its statistics. [Check]
- Glyde swooped in! [Encounter]
- An arrogant-smelling wind blows through. [Neutral]
- Glyde is thinking of new slang for the word "cool." Like "freakadacious." [Neutral]
- Glyde does fancy flips. [Neutral]
- Glyde sees its reflection and gets jealous. [Neutral]
- Glyde is giving itself a high five. ...somehow. [Neutral]
- Glyde is doing tons of flips to get your attention. [Neutral]
- You clap really sloppily. Glyde sucks up your praise like a vacuum cleaner. [Applaud]
- You clap like a gorilla. Glyde is becoming addicted to your praise. [Applaud #2+]
- You boo... but haters only make Glyde stronger. Glyde ATTACK UP+DEFENSE DOWN. [Boo]
- You do nothing. No effect. [Nothing]
- You do nothing. Glyde looks disappointed you aren't paying attention. [Nothing after Applauding twice]
- You do nothing. Glyde looks desperate for attention. [Nothing #2 after Applauding twice]
- You do nothing. Glyde leaves to look elsewhere for praise. [Nothing #3 after Applauding twice]
- Glyde is dying, but in a cool way. [Low HP]
- Glyde's name was likely decided by the Kickstarter backer who had Glyde put into the game. Glyde's name may come from the word gleyde, which can mean "a disagreeable old man," referring to Glyde's unpleasant demeanor. Glyde is also an obsolete spelling of glide, referring to how Glyde has no legs and can be seen as floating or levitating.
- There is a small glitch that allows Glyde to be encountered a bit easier: If Undertale is open in "windowed mode" and lets the window lose focus, the protagonist continues to march on the spot, which allows players to do something else during that time. Walking and alt-tabbing while fullscreen has the same effect. One can also hold the " Up [↑], Down [↓]" keys, approach the north wall and march on the spot that way.
- Glyde may be a reference to the Mortasheen monster, Twileye, in both shape and personality. Mortasheen is a fictional world full of monsters created by Jonothan Wojcik.