Enchanted creature's activated abilities can't be activated.
: Attach Detainment Spell to target creature.
9/25/2006 Detainment Spell prevents mana abilities of the enchanted creature from being activated.
9/25/2006 Morph isn’t an activated ability, so Detainment Spell doesn’t prevent face-down creatures from being able to turn face up.
9/25/2006 Responding to a creature’s activated ability being activated by moving Detainment Spell onto that creature won’t affect the ability that was just activated.