Djabu, Sanctuary Keeper

+2: Create an enchantment token with "When any player casts an instant, counter it and sacrifice this enchantment."
-1: Target creature you control gets -X/+X until end of turn where X is its current power. This can be used in any players turn multiple times.
-10: You skip your next turn. You get an emblem with "At the beginning of your upkeep, if you have 10 or more life, you win the game".