Unlikely Aid

Two spells stapled into one instant, and the pricing reflects a deliberate refusal to specialize. Indestructible until end of turn is combat insurance and board-wipe insurance both: it turns off lethal damage from any source (a burn spell, a fight or ping effect, a chump-blocking attacker, a Wrath of God) as well as every "destroy" effect. The +2/+0 rider means that protection also swings the race, so a defensive card doubles as an aggressive one. Black rarely gets clean indestructibility: its usual answers to death are recursion and drain, which makes this an unusual grant of a keyword the color does not natively keep around. The tension is that neither half is quite premium. The buff is small enough that it will not win a race alone, and indestructibility does nothing against exile, sacrifice, or bounce, which are exactly the answers black's opponents most often reach for. What two mana buys is a reactive window at instant speed: ambush an attacker, blank a favorable block, hold a committed creature through a wrath, or shrug off a targeted burn spell. This sits in the tradition of black tricks that ask the caster to leave mana up and read the board rather than commit proactively.