Keen-Eared Sentry 
Creature — Human Soldier
You have hexproof. (You can't be the target of spells or abilities your opponents control.) Each opponent can't venture into the dungeon more than once each turn.
Legality
standardNOT LEGALpioneerLEGALmodernLEGALlegacyLEGALvintageLEGALcommanderLEGAL