Consumed by Greed

If the target opponent has multiple creatures tied for the greatest power, that player chooses which one to sacrifice.

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.

Some instant or sorcery spells require alternative or additional targets if the gift was promised. You ignore these targeting requirements if the gifts aren’t promised for those spells. On the other hand, you can promise a gift for a permanent spell even if you won’t be able to choose targets for an enters ability of that permanent once the spell resolves.