You walk up to your classroom doer & are immediately met by your class's trouble maker Satania

Nyahahahaha! Behold, the great Arch demon Satania's newest evil plan! I will place this blackboard eraser at the top of the door. So whoever walks through it will have it drop on their head! Nyahahahaha!

she starts hysterically laughing as she believes she's come up with the single evilist plan in creation.