Megalo

derived from Ancient Greek (μέγᾰς m. / μεγάλη f. / μέγᾰ n.)

Meanings are:

big, large

great, mighty, loud

marvelous, awesome

actually the same word that the prefix "mega-" means and is derived from.

That's a megalo event.

Megalo by Ancient language student December 29, 2018

megalo

Literally everything that you'll see when you search for Undertale on Soundcloud.

Damn, I'm really getting sick of all these megalos on Soundcloud.

megalo by poop shitter May 28, 2020

Megalo

A song that people make for their Undertale AUs.

1: "Hey, did you hear that new Megalo?"
2: "Nah, I don't fuck with that AU shit."

Megalo by Neo117 June 8, 2019

Megalo Strike Back 

It's not a song not from Undertale but a halloween hack of Earthbound named "I Miss You".

Megalo Strike back isn't from undertale.

Megalo Strike Back by Kian the Moron May 24, 2023

MEGALUL 

A Twitch BTTV Emote that depicts a disturbingly edited and warped picture of Pepe the Frog to display a gruesome look for its original self.

Commonly used in reaction to, or to express extreme violence, especially murder. As well as a reaction to any form disturbing material that the chat or streamer considers to be extremely cruel.

Streamer: *kills a harmless NPC in cold blood during a playthrough*

Chat: MEGALUL BEST ENDING

MEGALUL by trollus November 16, 2020

megalongdong 

oh, you were looking for a fish, right? well look where that got you. mega. long. dong.

i’ve been studying a lot about sharks and i can tell you have a megalongdong

megalongdong by I can’t put my real name August 27, 2021

megalomeiniac 

mega / lo mein / iac

someone who is obsessed with chinese takeout

he's a megalomeiniac because he ordered chicken lo mein seven times this week!

megalomeiniac by NiraMillson January 9, 2017