Gaster

A mysterious figure talked about in the game UNDERTALE made by Toby Fox through entities called "Gaster Followers". Gaster Followers can only be obtained through getting certain numbers on an RNG system called "FUN value." The Gaster Followers will hint at what Gaster was and what he did. A hallway can appear in the Waterfall area if you have a FUN value of 66, but there is a 10% chance while have FUN value 66 that a mysterious door will appear. An entity is spotted when going through the door. It is highly speculated that this person might be Gaster, as when you interact with him, he plays a sped up and reversed version of Gaster's Theme

"Gaster? Who is that? I've never heard someone with that name before.."

by personusingtheurbandictionary September 6, 2025

Gastered

"To get gastered" means "To disappear mysteriously without a trace", or "To get trapped in void"

Dess clearly got voided, gastered, bunkered, whatever you want to call it.

by thecrazybeewastaken December 29, 2023

GASTER

❄︎☟︎☜︎ 💣︎✌︎☠︎ 💧︎🏱︎☜︎✌︎😐︎✋︎☠︎☝︎ ☟︎✌︎☠︎👎︎💧︎📬︎
☼︎⚐︎✡︎✌︎☹︎☜︎ 💧︎👍︎✋︎☜︎☠︎❄︎✋︎💧︎❄︎ ❄︎☟︎✌︎❄︎ ☞︎☜︎☹︎☹︎ ✋︎☠︎❄︎⚐︎ ☟︎✋︎💧︎ ⚐︎🕈︎☠︎ 👍︎☼︎☜︎✌︎❄︎✋︎⚐︎☠︎📪︎ ❄︎☟︎☜︎ 👍︎⚐︎☼︎☜︎📬︎
💧︎⚐︎💣︎☜︎👎︎✌︎✡︎ ☟︎☜︎ 🕈︎✋︎☹︎☹︎ 👍︎⚐︎💣︎☜︎ 👌︎✌︎👍︎😐︎📬︎

gaster? don't know that guy..

by ☞︎⚐︎☼︎☝︎⚐︎❄︎❄︎☜︎☠︎ 👍︎☟︎✋︎☹︎👎 March 21, 2023

Gaster

This specific Gaster is the one from Gasterhub. Yeah, this porn meme is about himself. He's a discord mod, just like the other ones, and by the time this gets posted, he's on a break (l bozo). His weight is unknown, and the dude is a blue dragon (note: the blue dragon meaning made him have PTSD). That's it for this dude.

"So what's Gasterhub?"

"It's about Gaster the blue dragon."

Gaster is his username but you'll never know his tag

by Zeorn May 26, 2022

Wing Gaster

The royal scientist!

"Im wing gaster! The royal scienti-AAAAAAH"

by Chezboi the evil October 9, 2025

wing gaster

hi! im wing gaster! i hate the giggler cult.

hi! im wing gaster! i hate the giggler cult.

by yeit August 30, 2024

Gaster Effect

The Gaster Effect (Undertale term) is when a person mistakenly links anything slightly mysterious, or anything slightly resembling Gaster (leitmotifs, font or face) relating to Undertale or Deltarune, to the character W.D. Gaster, even if it is very hard. This is usually because Gaster is very mysterious and of a certain significance to said games' lore. In most cases, relating things to Gaster is not appropriate for the situation and/or possibly misleading.

A: Woah that new Deltarune song has Gaster's Theme playing at 0:44! If you listen to the piano...
B: Those are just arpeggios. You've got the Gaster Effect

by Stratollera April 15, 2024