If I kill my own unit in reaction to Falling Star being cast (leaving me with no units), does my opponent have to target their own units? Can they target the same unit twice even if it would die from the first damage trigger?

Ruling: When Falling Star is cast, it creates two reflexive triggers that go on the stack simultaneously. The caster must choose all targets for both triggers at that moment, before any damage resolves. If the opponent has no valid targets, the caster must target their own units.

Sequence:

• Falling Star is cast
• Two "deal 3 damage" triggers are created and go on the stack simultaneously
• All targets for both triggers must be chosen immediately
• Players can then react before each trigger resolves
• Damage resolves one trigger at a time

Nuances:

• The same unit can be targeted twice, even if it has less than 4 Might, because targets are locked in before any damage resolves
• This same targeting mechanic applies to other similar cards like Icathian Rain