Prison Term is a uncommon Enchantment — Aura card from Shadowmoor (SHM), collector number 18. Current market price: $1.54 (foil $5.34), TCGplayer market prices via Scryfall.
Enchant creature Enchanted creature can't attack or block, and its activated abilities can't be activated. Whenever a creature an opponent controls enters, you may attach this Aura to that creature.