Mire Blight

Oracle Text

Enchant creature

When enchanted creature is dealt damage, destroy it.

Card Rulings

10/1/2009 Mire Blight’s ability triggers when the enchanted creature is dealt any kind of damage, not just combat damage.
10/1/2009 If Mire Blight’s ability triggers, the creature it was enchanting at that time is the one that will be destroyed when the ability resolves. It doesn’t matter if Mire Blight leaves the battlefield or somehow becomes attached to another creature by that time.