Creature — Angel 5/5, 4WW (6)
Rare
Flying
When Aegis Angel enters the battlefield, another target permanent is indestructible for as long as you control Aegis Angel. (Effects that say "destroy" don't destroy that permanent. An indestructible creature can't be destroyed by damage.)
Illus. Aleksi Briclot

9/22/2011: If Aegis Angel leaves the battlefield, you no longer control it.
9/22/2011: If another player gains control of Aegis Angel, the permanent will no longer be indestructible, even if you regain control of Aegis Angel.
9/22/2011: If Aegis Angel and the permanent would be destroyed simultaneously, only Aegis Angel will be destroyed.
Legal in Vintage (Type 1)
Legal in Legacy (Type 1.5)
Legal in Extended (Type 1.X)
Legal in Classic (MTGO)
Legal in Commander
Legal in Modern