Enchantment — Aura, 4{B/G} (5)
Common
Enchant creature
As long as enchanted creature is black, it gets +1/+1 and has deathtouch. (Any amount of damage it deals to a creature is enough to destroy that creature.)
As long as enchanted creature is green, it gets +1/+1 and all creatures able to block it do so.
Illus. Steve Prescott

8/1/2008: If the enchanted creature is both of the listed colors, it will get both bonuses.
Legal in Vintage (Type 1)
Legal in Legacy (Type 1.5)
Legal in Classic (MTGO)
Legal in Commander
Legal in Modern