Onyx, Blade of Vengeance

+2: Target creature gains double strike and Deathtouch until end of turn.
-1: Until end of turn this Onyx, becomes a 6/6 with double strike, menace and trample.
-10: Summon 3 1/1 assassin token creatures with: "Whenever this creature deals combat damage to a player, that player loses the game"