Enchantment — Aura, U (1)
Common
Enchant creature
Enchanted creature gets +2/+0.
At the beginning of the upkeep of enchanted creature's controller, put a -0/-1 counter on that creature.
Never underestimate the power of the soul unleashed.
Illus. Richard Kane Ferguson

10/1/2008: The -0/-1 counters stay on the creature even if Essence Flare is removed.
Legal in Vintage (Type 1)
Legal in Legacy (Type 1.5)
Legal in Classic (MTGO)
Legal in Commander