1. Your opponent activates Mirror Force: This is a Trap Card that destroys all attacking monsters your opponent controls.
2. You activate Negate Attack: This is a Spell Card that negates the activation of a monster's attack.
3. Your opponent activates Trap Stun: This is a Trap Card that negates the activation of a Spell/Trap Card.
The order of activation matters:
* Trap Stun is activated first: This negates the activation of Negate Attack. Negate Attack fails to resolve, and Mirror Force remains active. The Mirror Force effect will trigger, destroying all your attacking monsters.
* Negate Attack is activated first: This negates the activation of Mirror Force. Mirror Force fails to resolve, and Trap Stun has no target to activate against. You can continue your attack.
Therefore, the outcome depends on the timing of the Trap Stun activation:
* If Trap Stun is activated before Negate Attack: Your opponent's Mirror Force will activate, destroying your attacking monsters.
* If Negate Attack is activated before Trap Stun: Your opponent's Mirror Force will be negated, and your attack will continue.
Key takeaway: The outcome is determined by the chain of card activation and the order in which they resolve.