You may cast Armor of Thorns as though it had flash. If you cast it any time a sorcery couldn't have been cast, the controller of the permanent it becomes sacrifices it at the beginning of the next cleanup step.
Enchant nonblack creature
Enchanted creature gets +2/+2.
10/1/2009 The sacrifice occurs only if you cast it using its own ability. If you cast it using some other effect (for instance, if it gained flash from Vedalken Orrery), then it won’t be sacrificed.