Thopter Arrest
{2}{W}
Enchantment
Oracle Text
When this enchantment enters, exile target artifact or creature an opponent controls until this enchantment leaves the battlefield.
Watch Out
ETB trigger, not a cast triggerRules Note
This card's ability triggers when it enters the battlefield, not when it's cast. Effects that double ETB triggers (like Panharmonicon) work here. Countering the spell prevents the creature from entering, so the ETB won't fire.