Mr.Funsocks means one of two things:
1.) A sock that you masterbate in and then put it on your friend's face while he's sleeping and then take pictures and put it on the internet.
2.) The coolest guy in the world with the most creative name in the world
Examples in order
1.) Paul: Dude! I put Mr.Funsocks on John last night!
Dustin: Did he lick it?!?!
2.) Mr.Funsocks will kill you in Halo 2, and cnc