Wormfang Crab 
Creature — Nightmare Crab
This creature can't be blocked. When this creature enters, an opponent chooses a permanent you control other than this creature and exiles it. When this creature leaves the battlefield, return the exiled card to the battlefield under its owner's control.
Legality
standardNOT LEGALpioneerNOT LEGALmodernNOT LEGALlegacyLEGALvintageLEGALcommanderLEGAL