Keen-Eared Sentry (AFR) from Adventures in the Forgotten Realms, available at 401 Games Canada.

• Rarity: Uncommon
• Finish: Normal
• Artist: Viko Menezes
• Card Text:
  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.