Primal Cocoon 
Enchantment — Aura
Enchant creature At the beginning of your upkeep, put a +1/+1 counter on enchanted creature. When enchanted creature attacks or blocks, sacrifice this Aura.
Legality
standardNOT LEGALpioneerNOT LEGALmodernLEGALlegacyLEGALvintageLEGALcommanderLEGAL