Oracle of Bones

If you want to cast a card this way, you cast it as part of the resolution of the triggered ability. Timing restrictions based on the card’s type (such as sorcery) are ignored. Other casting restrictions (such as “Cast [this card] only before attackers are declared”) are not.

Players can’t respond to the tribute decision before the creature enters the battlefield. That is, if the opponent doesn’t pay tribute, the triggered ability will trigger before any player has a chance to remove the creature.

If the opponent pays tribute, the creature will enter the battlefield with the specified number of +1/+1 counters on it. It won’t enter the battlefield and then have the +1/+1 counters placed on it.

If you cast a card “without paying its mana cost,” you can’t pay alternative costs such as overload costs. You can, however, pay additional costs such as kicker costs. If the card has mandatory additional costs, you must pay those.

The triggered ability will resolve even if the creature with tribute isn’t on the battlefield at that time.

If the triggered ability has a target, that target will not be known while the creature spell with tribute is on the stack.