When playing Mystic Reversal in reaction to a spell, do you take control of only the spell you're reacting to, or can you choose any spell currently on the chain?

Ruling: You can choose to take control of any spell currently on the chain, not just the spell you're reacting to.

Nuances:

• You can optionally let spells resolve first before playing Mystic Reversal in reaction to an earlier spell on the chain