The Arena Masters

+1: Each player reveals the top card of their library. Each player that reveals a legendary creature or planeswalker this way draws a card.
-1: Two target creatures get -1/-1 until end of turn. Tap those creatures.
-7: You get an emblem with "When a creature or PW ETBs, you may have another creature get -X/-X until end of turn, where X is that spells mana cost."