The Ghost of a Tiny Bit of Cheese

This morning, Oliver told me that all of the ghosts and zombies and skeletons are "under his command." All except one.

"Which one isn't under your command?" I asked. Inquiring minds want to know.

"The ghost of a tiny bit of cheese."

"Oh. Well, what does the ghost of a tiny bit of cheese do?"

He paused for just a moment. "It runs away from the mouse ghost..."