Creartheist 

Someone who creates their own god or religion.

Guy 1: I heard Sam say he worships a god named Koi? I can’t find anything on a god named that.
Guy 2: Sam is a creartheist. That must be his own god.

Creartheist by itsybitsytestimony July 31, 2023

cartheist 

A person who films in their car YouTube videos which espouse, defend, or attempt to justify religion. (Vertical video is optional, but frequent.)

"Oh, jeepers, not another cartheist! Why do you all film in your stupid car???"

cartheist by BionicDance June 8, 2019