I havent played MUGEN in a while. Last game I had was something like 2 years ago. I'd downloaded it and it had tons of characters I'd never even heard of. Some of them were REALLY in depth, and I dont know if they were actual characters or original creations.
One that stood out was extremely sexual, and hilarious but could be construed as offensive. I think she was a nurse with huge boobs (clearly, out and swinging) and some of her moves involved her using her uh... juices? to attack. It was really weird but funny.
I remember the MUGEN scene being pretty a-hole-ish as well. Though some of the characters were pretty cool, like Ogre, who was a super-super-suped up version of Akuma with moves from Grant, Yamazaki, etc. Also Evil Ken and Ryu were pretty cool.
I wonder if the "Violent Ken" character from SNK Vs Capcom SVC Chaos was influenced by Evil Ken. His stance was pretty close to the Evil Ken character in MUGEN games I'd seen.