Volrath's Curse
Tempest — common
Enchantment — Aura
Volrath's Curse rulings:
2016-06-08: Activated abilities contain a colon. They’re generally written “[Cost]: [Effect].” Some keywords are activated abilities and will have colons in their reminder text.
2004-10-04: If the creature this card is on is sacrificed to this card, this card is put into the graveyard before the ability to unsummon it can be used.