It's Crochetface! Fourth of 5 dolls in my Crochetklok series. This one gets a solo shot because, yes, I own his knife. Bought it at NYAF '08 because I thought it was cool, then I got into Metalocalypse a few months later, watched Dethfam, and squee'd all over the house. Must'a been pretty scary for everyone else in the house, as I was brandishing the knife the entire time.
I altered patterns for other plushies from a book I've got to make these guys, and planned all the colors, features, etc. myself.
Dethklok, Metalocalypse, and William Murderface ain't mine, only this off-puttingly adorable plushie. The knife can be purchased from Griffin's Claw Armory (check your local Comic Con, they're probably there), it's called the "Dragon's Claw."