Someone who has been snowboarding forever but somehow still rips it while other people his/her age are old and decrepit. It implies that he/she has been snowboarding since the time of dinosaurs.
Bro 1: "Dude! That guy's been shreddin' this place forever!" Bro 2: "I know, he's a shredasaurus!"
by otirhub July 15, 2010