For Falling Star, do you choose both targets before any damage goes off, or can you choose targets sequentially after seeing opponent reactions?

Ruling: You choose both Falling Star targets at the same time when the spell resolves and creates its reflexive triggers. Once those targets are declared and the triggers are on the chain, you cannot change them regardless of what your opponent does afterward.

Sequence:

• Cast Falling Star (no targets chosen yet)
• Pass priority; opponent can react
• If no reaction, Falling Star resolves and creates two reflexive triggers
• You choose both targets at this moment and put both triggers on the chain
• Pass priority; opponent can now react to the triggers themselves
• Each trigger resolves sequentially, dealing 3 damage

Nuances:

• Your opponent can wait until after you've locked in targets to play units (like revealing a hidden Teemo), and you cannot redirect damage to the new unit
• If you prematurely declare targets when casting Falling Star (even though you shouldn't), you are forced to stick with those choices if they remain legal
• If the opponent removes all legal targets before Falling Star resolves, you must target your own units