Unstable Mutation
Enchantment - Aura (CMC 1)
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.
Decks with Unstable Mutation
[UMA] Ultimate Masters #80 (U)
[TSB] Time Spiral Timeshifted #33 (S)
[5ED] Fifth Edition #131 (C)
[4ED] Fourth Edition #110 (C)
[3ED] Revised Edition #86 (C)
[ARN] Arabian Nights #22 (C)
[FBB] Foreign Black Border #86 (C)
[4BB] Fourth Edition Foreign Black Border #110 (C)
[SUM] Summer Magic / Edgar #86 (C)