Unwilling Vessel
Creature — Human Wizard
Oracle Text
Vigilance
Eerie — Whenever an enchantment you control enters and whenever you fully unlock a Room, put a possession counter on this creature.
When this creature dies, create an X/X blue Spirit creature token with flying, where X is the number of counters on this creature.
Watch Out
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.
'Dies' means 'put into a graveyard from the battlefield.' If a creature is exiled instead of dying (Swords to Plowshares, Rest in Peace), dies triggers won't fire. Tokens do trigger 'dies' abilities briefly before ceasing to exist.