Dust Stalker 
Creature — Eldrazi
Devoid (This card has no color.) Haste At the beginning of each end step, if you control no other colorless creatures, return this creature to its owner's hand.
Legality
standardNOT LEGALpioneerLEGALmodernLEGALlegacyLEGALvintageLEGALcommanderLEGAL