When Chemtech Enforcer and Noxian Drummer move together into an enemy occupied battlefield, why does the Drummer's 'when I move' trigger resolve before the showdown, and is the Enforcer still a 2/2 (not yet having Attacker designation)?

Ruling: The movement is performed and triggers become pending. During cleanup, the showdown is marked as staged and pending triggers are put on the chain. The showdown cannot begin because the game is in a Neutral Closed state (chain is not empty).

Sequence:

• Units perform movement
• "When I move" trigger becomes pending
• Cleanup occurs: showdown is marked as staged AND pending trigger is added to the chain
• Chain must resolve before showdown can begin (can't start showdown in Neutral Closed state)
• Therefore Enforcer has not yet received Attacker designation when the trigger resolves

Nuances:

• Showdown cannot start while the chain is not empty
• The game must be in a neutral open state to begin showdown