Can you react to the reflexive triggers put on the chain by Falling Star after targets are chosen, such as by bouncing the targeted unit to make the effects mistarget?

Ruling: Yes, you can react to the reflexive triggers from Falling Star after they are put on the chain with targets chosen. For example, you could use a reaction to bounce the targeted unit back to hand, causing the triggers to mistarget and fail.

Sequence:

• Falling Star resolves with no targets chosen initially
• Two "deal 3 to a unit" reflexive triggers are put on the chain separately, with targets chosen for each
• Players can react to these triggers after targets are chosen
• The triggered abilities resolve one at a time in the opposite order they were put on the chain

Nuances:

• You cannot Wind Wall the Falling Star spell itself at this point, only react to the individual triggers
• Deflect costs are paid for each trigger as you put each one on the chain