A kirby is someone who is a huge baller. Usually someone who made countless amounts of baller-ass dollars selling from starring in kids video games, or selling tasty Chinese food from a large chain. A kirby will often own 10 cars of the same model, just so they don't get bored.
"Nah bro, that guy with the MC12 ain't no poser. He's a straight kirby"
"Dude I was up in the club last, and this crazy-ass kirby was making paper airplanes out of $500 bills and throwing them at people." - "You mean the little pink guy that runs around with a treasure chest on his head?" - "No bro, a kirby - a straight baller" - "oh, my bad"