Sleeper's Guile is a common Enchantment — Aura card from Urza's Legacy (ULG), collector number 67. Current market price: $0.17 (foil $2.69), TCGplayer market prices via Scryfall.
Enchant creature Enchanted creature has fear. (It can't be blocked except by artifact creatures and/or black creatures.) When this Aura is put into a graveyard from the battlefield, return it to its owner's hand.