Wildfire Howl

You can’t pay a gift cost more than once.

If the gift was promised and the target is illegal as Wildfire Howl tries to resolve, it won’t resolve and none of its effects will happen. No creatures will be dealt damage.

As an additional cost to cast a spell with gift, you can promise the listed gift to an opponent. That opponent is chosen as part of that additional cost. The gift isn’t given at this time; rather, it’s given at a later time based on whether or not the spell is a permanent spell.

In the main set, there are four different kinds of gifts. “Gift a Food” causes the chosen opponent to create a Food token, while “Gift a Treasure” causes the chosen opponent to create a Treasure token. “Gift a card” causes them to draw a card, and “Gift a tapped Fish” causes them to create a tapped 1/1 blue Fish creature token. The Commander decks contain two more kinds of gifts: “Gift an Octopus,” which causes the chosen opponent to create an 8/8 blue Octopus creature token, and “Gift an extra turn,” which causes them to take an extra turn after the current turn ends.

If a spell for which the gift was promised is countered, doesn’t resolve (perhaps because all of its targets are illegal), or is otherwise removed from the stack, the gift won’t be given. None of its other effects will happen either.

For permanent spells with gift, an ability triggers when that permanent enters if the gift was promised. When that ability resolves, the gift is given to the appropriate opponent.