Fatgrampa 

A skilled youtuber who makes fortnite content. He seems basic but he has many skills and knows what hes doing

Omg, Hes such a fatgrampa

Fatgrampa by Yoittt March 11, 2019

Fatrapanin 

To be or Past tense of the adjective "crazy"

Boy #1: Hey, wanna' go steal some cats?
Boy #2: Bro, are you fatrapanin? Were gonna get caught!

Fatrapanin by TFFM21 July 7, 2009