Ailla, the Swiftkiller

+1: Ailla, the Swiftkiller deals X damage to target creature or player, where X is the number of experience counters you have.
0: Until the end of the turn, Ailla, the Swiftkiller becomes a 3/1 red assassin creature with double strike. Prevent all damage dealt to it.
-2: You gain 2 experience counters.