When do you announce the targets for Dragon's Rage - on cast or when resolving the spell?

Ruling: Targets are never selected on resolution. Dragon's Rage targets a unit on activation (the unit to be moved and the destination), and then creates a reflexive trigger that targets another unit at the destination.

Sequence:

• First part: On activation, target an enemy unit and declare a destination. This moves the unit.
• Second part: After the move resolves, a reflexive trigger enters the chain that targets an enemy unit at the previously declared destination to deal damage.
• You can respond to either part of Dragon's Rage.

Nuances:

• If no move is performed, the reflexive trigger never enters the chain.
• To counter Dragon's Rage, move the targeted unit to the destination before the first part resolves - this prevents the move from happening and stops the reflexive trigger from entering the chain.
• Moving the unit in response to the first part won't prevent the move if the origin and destination are still different.
• A move requires choosing an origin and destination that are different from each other.
• If the unit is moved to a battlefield, you can use Flash in response to the reflexive trigger. If moved to your base, Flash will not save the unit.