Common Q&As: Knowledge Pool revisited

After my original article was posted on Tapped Out, I received several questions. I'm going to address those here.

Q: What happens to spells with X in the casting cost?

A: When these spells are cast out of exile with Knowledge Pool, X=0.

Q: What about spells with rebound?

A: Recall the definition of rebound:

If you cast this spell from your hand, exile it as it resolves. At the beginning of your next upkeep, you may cast this card from exile without paying its mana cost.

Since the original spell cast from your hand is exiled before it resolves, rebound does nothing. When the spell is cast from exile with Knowledge Pool, rebound does nothing since the spell must be cast from your hand. To recap: rebound and Knowledge Pool just don't mesh.

Q: How do different card type timings work?

A: All spells cast from your hand must obey all card timings. However, when a spell is cast from exile with Knowledge Pool, you can play any spell. For example, if you play an instant during your opponent's turn, you can cast a creature spell out of exile. However, if any card specifically says it can't be played at a certain time, then it must be obeyed.

Note: Lands are not spells. If a land is exiled with Knowledge Pool's imprint ability, then it is simply exiled.