Gulgas is a character created by me. I wanted to have a character that took Bill Cipher's place in Under Falls.
I didn't want Asriel, Chara or others from Undertale to be the enemy, so I created my own.
Gulgas's name and design is based after the Earthbound/Mother-villain Giygas/Giegue.
[NOTE: If you want to use Gulgas for your (UnderFalls) art, then send me a note and tell me before you do it. And tell your viewers that the character belongs to me. DO NOT USE THIS OR ANY OF MY CHARACTERS WITHOUT MY PERMISSION!!!]
This is a character I created for UnderFalls (Undertale/GravityFalls - the characters from Undertale are taking the places of the GravityFalls-characters). Like for example, Frisk/Chara(nearing ending/last "season") is taking Mabel's place, Flowey(in the beginning)/Asriel(all adventures) is taking Dipper's place, Asgore(called sometimes "daddy Asgore" from Frisk)/Sans(known as Dunkle Sans by Frisk and Asriel (get it?? Dunk-le? Like from when he says: Gettttttt DUNKED on!) and Mr. Skeleton/Dr. Skeleton/Mr. Mystery Skeleton/Dr. ***** by public) is taking Grunkle Stan's place, and Gulgas is taking Bill Cipher's place, etc.