Not sure if bug but you can make scuttle crab give up on life
http://i.imgur.com/hE2wmXu.jpg
So the way it works is you push him down to one side and then when he dashes the other way you hop just before that and you'll land in front of him. He'll just go to the corner and cry because hates life
He sits there and doesn't move while you throw spears in to his undeserving back side.