Phyrexian Gremlins

Creature - Ouphe 1/1, 2B (3)
You may choose not to untap Phyrexian Gremlins during your untap step.
{T}: Tap target artifact. It doesn't untap during its controller's untap step for as long as Phyrexian Gremlins remains tapped.¹
Illus. Amy Weber

Gatherer Card Rulings [Nov 2009]

• 10/4/2004: If the Gremlins somehow become an artifact and then tap themselves, they can never be untapped during the untap phase. They must be untapped by an external effect.
• 10/4/2004: Only prevents the artifact from untapping during untap step. Ones that untap during upkeep are not inhibited.
• 10/4/2004: The target artifact can't untap if the Gremlins and the artifact are tapped during untap, even if it is your artifact, and you plan on untapping the Gremlins.
• 10/4/2004: The effect does not end if the target stops being valid. For example, if it stops being an artifact.
• 10/4/2004: Can target a tapped artifact.

Format Legality	Legal in Vintage, Legacy Banned in Extended, Standard
Printings (1/1)	Antiquities (Common)