Shaco is the jungle Teemo.
Yes. Shaco is as annoying in jungle as Teemo is in lane. He just two shots you at any point in the game. He has flash built into his kit to the point he takes smite and ignite. He can be invisible. He can come to your jungle and do what he wants. You try to fight him? You die. You try to run? He chases you and kills you. Your teammates arrive? He disappears/flashes into some walls. You can't do anything. Literally. Unless he does something incredibly stupid, he ha s no counterplay. You don't see him. You have less damage than him. He has more escapes than you. How fun, right?