Arbalest Elite

• WWizards of the Coast2011-09-22
  Official Ruling
  If another player controls Arbalest Elite during your next untap step, the part of the effect that keeps it from untapping does nothing. It won't try to apply during a future untap step.
• WWizards of the Coast2011-09-22
  Official Ruling
  If the creature is an illegal target when Arbalest Elite's ability tries to resolve, the ability won't resolve and none of its effects will happen. Arbalest Elite will untap during its controller's next untap step.

Rulings via Scryfall