A-Thornmantle Striker 
Creature — Elf Rogue
When Thornmantle Striker enters, choose one — • Remove X counters from target permanent, where X is the number of Elves you control. • Target creature an opponent controls gets -X/-X until end of turn, where X is the number of Elves you control.
Legality
standardNOT LEGALpioneerNOT LEGALmodernNOT LEGALlegacyNOT LEGALvintageNOT LEGALcommanderNOT LEGAL