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.
Legality
standardNOT LEGALpioneerNOT LEGALmodernNOT LEGALlegacyLEGALvintageLEGALcommanderLEGAL