Ironclaw Curse 
Enchantment — Aura
Enchant creature Enchanted creature gets -0/-1. Enchanted creature can't block creatures with power equal to or greater than the enchanted creature's toughness.
Legality
standardNOT LEGALpioneerNOT LEGALmodernNOT LEGALlegacyLEGALvintageLEGALcommanderLEGAL