Can Defy target any spell on the chain, or only the most recently played one? Can an opponent intentionally play a cheap spell followed by an expensive one to avoid Defy?

Ruling: Defy can target any valid spell on its chain, not just the most recently played one. An opponent cannot avoid Defy by playing a cheap spell followed by an expensive one.

Nuances:

• The chain resolves one item at a time, not all at once
• After each spell resolves, priority is given to players before the next spell resolves
• A player retains priority after playing a spell until they explicitly pass priority
• A player can play multiple reactions while holding priority without passing