$15.59

Unstable Mutation 
Enchantment — Aura
Arabian Nights Common
Enchant creature
Enchanted creature gets +3/+3.
At the beginning of the upkeep of enchanted creature's controller, put a -1/-1 counter on that creature.
Enchanted creature gets +3/+3.
At the beginning of the upkeep of enchanted creature's controller, put a -1/-1 counter on that creature.
Illus. Douglas Shuler