Artifact Creature — Scarecrow 2/2, 4 (4)
Uncommon
Wither (This deals damage to creatures in the form of -1/-1 counters.)
When Lockjaw Snapper dies, put a -1/-1 counter on each creature with a -1/-1 counter on it.
Illus. Daren Bader

5/1/2008: Each of those creatures will get just one new -1/-1 counter, regardless of how many it already has.
Legal in Vintage (Type 1)
Legal in Legacy (Type 1.5)
Legal in Classic (MTGO)
Legal in Commander
Legal in Modern