Phyrexian Gremlins
Creature — Phyrexian Gremlin
You may choose not to untap this creature during your untap step.
: Tap target artifact. It doesn't untap during its controller's untap step for as long as this creature remains tapped.
Amy Weber
Antiquities (ATQ)
• #18Rulings
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.
(wotc • 2004-10-04)
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.
(wotc • 2004-10-04)
The effect does not end if the target stops being valid. For example, if it stops being an artifact.
(wotc • 2004-10-04)
Can target a tapped artifact.
(wotc • 2004-10-04)
Only prevents the artifact from untapping during untap step. Ones that untap during upkeep are not inhibited.
(wotc • 2004-10-04)
Rulings
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.
(wotc • 2004-10-04)
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.
(wotc • 2004-10-04)
The effect does not end if the target stops being valid. For example, if it stops being an artifact.
(wotc • 2004-10-04)
Can target a tapped artifact.
(wotc • 2004-10-04)
Only prevents the artifact from untapping during untap step. Ones that untap during upkeep are not inhibited.
(wotc • 2004-10-04)