How do reflexive triggers from spells like Falling Star and Icathian Rain work? Specifically: (1) When are targets declared? (2) Can opponents respond after the reflexive triggers are added to the chain? (3) What happens if a targeted unit moves or is removed before resolution?

Ruling: Reflexive trigger spells like Falling Star and Icathian Rain do not target on cast. When they resolve, they create reflexive triggers that are added to the chain, and targets are declared at that point. Opponents can respond after each individual reflexive trigger is added to the chain and between each trigger's resolution.

Sequence:

• You play Falling Star
• Players can react here
• Falling Star resolves, putting 2 reflexive triggers on the chain
• You pick targets for the 2 reflexive triggers
• You pay additional costs (e.g., for deflect)
• Players can react here
• First trigger resolves dealing 3 damage
• Players can react here
• Second trigger resolves dealing 3 damage

Nuances:

• Target legality is checked at resolution in Riftbound
• If a target becomes illegal at resolution, instructions requiring that legal target are ignored, but other instructions still resolve (DAMAYC)
• If only your own units exist when reflexive triggers are added to the chain, you must target your own units (you cannot choose to not target if legal options are available)
• If an opponent removes all their units before the original spell resolves (e.g., using Gust in response to Falling Star cast), you must target your own units when the reflexive triggers are created
• If an opponent removes a unit after it's been targeted by a reflexive trigger (e.g., using Gust in response to the reflexive trigger itself), no damage is dealt to that target
• Counterspells like Wind Wall can only counter the original spell cast, not the reflexive triggers added to the chain afterward