The most merciless, brutal, and hilarious parody on rap, hip hop, and the very fiber of pop culture in general. You have probably heard his 'hit' songs 'I'm A Gangster', or 'Fanny Pack'. I highly recommend checking out his other stuff.
Some of my favorites:
Yo, I'm Really Cool
Bark With Me If You're My Dog
Curse In Your Verses
Note: you may have heard of Josh Tobin, or Josh Katz, they are both just Rappy McRapperson though.