Prison Term | Magic: The Gathering
Formats Prison Term is Legal in
Official Oracle Text for Prison Term
Enchanted creature can't attack or block, and its activated abilities can't be activated.
Whenever a creature enters the battlefield under an opponent's control, you may attach Prison Term to that creature.
Official Rulings for Prison Term
7/1/2013 : Activated abilities contain a colon. They're generally written "[Cost]: [Effect]." Some keywords are activated abilities; they have colons in their reminder text.