Arbalest Elite
Creature — Human Archer
, 
: This creature deals 3 damage to target attacking or blocking creature. This creature doesn't untap during your next untap step.
There are few things as satisfying as a good, healthy thunk.
Chris Rahn
Magic 2012 (M12)
• #5Rulings
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.
(wotc • 2011-09-22)
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.
(wotc • 2011-09-22)
Rulings
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.
(wotc • 2011-09-22)
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.
(wotc • 2011-09-22)