Slendytubbies: One with the Mask

Oliver is a simple 13 year old teen with a short temper and a boring life in school. However, he always found enjoyment in horror games, especially Slendytubbies. He has even created his own OC tubby survivor, a black tubby with a scary grey mask.
One day, however, he somehow finds himself in the world of Slendytubbies 3, reincarnated as his own slendytubbie OC. Shocked and anxious to get back home, he makes his way through the story and the characters, before realising the changes he can make to this universe.

#1 in Slendytubbies on 15/02/2022 somehow...

This is an OC insert of slendytubbies I once thought of, based on other slendytubbies stories I've read here, so some parts may have some similarities with others.