Because they have slow-moving hands.
Why should you never play pound-it with a skeleton?
Because they don't have any skin.
Why couldn't the skeleton win at pound-it?
He kept boning up.
Why did the octopus lose at hide-and-seek?
He kept getting kracken up.
Why is it hard to play hide and seek with Dracula?
Because he's always in his coffin.
Why are ghosts such bad liars?
Because you can see right through them.