A guy/girl with an excessively large ass with a bountiful amount of cellulite. He/she is usually emotionally unstable and can be quite annoying.
You: Look at Sophia! Her ass is hanging so low from all that cellulite.
Friend: And to top it off, she's super annoying too!
You: She's definitely a Cartman Fatass!
Friend: And to top it off, she's super annoying too!
You: She's definitely a Cartman Fatass!
by Psycho-kitty May 7, 2014