The Knives were the secondary antagonists who only appeared in the Annoying Orange episode, The Fruitrix. They were basically on a mission to defeat Orange for an unknown reason. One of them was about to succeed before Orange took the red pill and went to the real kitchen. When he returned, 10,000 more of them attempted to kill him again. Orange fought the head knife and destroyed him, then used a maximum motorboat to destroy the rest, alongside the evil machines.
Annoying Orange Wiki