Arena of the Ancients
{3}
Artifact
Oracle Text
Legendary creatures don't untap during their controllers' untap steps.
When this artifact enters, tap all legendary creatures.
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.