When Thopter Arrest enters the battlefield, exile target artifact or creature an opponent controls until Thopter Arrest leaves the battlefield.
2/9/2017 If Thopter Arrest leaves the battlefield before its triggered ability resolves, the target permanent won’t be exiled.
2/9/2017 Auras attached to the exiled permanent will be put into their owners’ graveyards. Any Equipment will become unattached and remain on the battlefield. Any counters on the exiled permanent will cease to exist.
2/9/2017 If a token is exiled this way, it will cease to exist and won’t return to the battlefield.
2/9/2017 The exiled card returns to the battlefield immediately after Thopter Arrest leaves the battlefield. Nothing happens between the two events, including state-based actions.
2/9/2017 In a multiplayer game, if Thopter Arrest’s owner leaves the game, the exiled card will return to the battlefield. Because the one-shot effect that returns the card isn’t an ability that goes on the stack, it won’t cease to exist along with the leaving player’s spells and abilities on the stack.