Creature — Homunculus 0/4, 1U (2)
Common
Defender
{2}{U}, {T}: Target player puts the top X cards of his or her library into his or her graveyard, where X is the number of creatures with defender you control.
One piercing stare usually convinces thieves to go elsewhere.
Illus. Kev Walker

10/1/2012: The number of creatures with defender you control is counted when the ability resolves.
Legal in Vintage (Type 1)
Legal in Legacy (Type 1.5)
Legal in Extended (Type 1.X)
Legal in Standard (Type 2)
Legal in Classic (MTGO)
Legal in Commander
Legal in Modern