Play this during any action or attack. This can be even during another players turn. Once played that action or attack is cancelled.
In the case of interrupting a card with multiple attacks such as Fishing Frigate or Rampaging Cassowary, you only prevent the remaining attacks. So if a rival player uses a Rampaging Cassowary on another rival and then selects you and you cancel the attack, you will only prevent the remaining attacks and the original rival still has their card discarded.
The Falcon Interceptor can also cancel another Falcon Interceptor or Bouncing Penguin, which results in the original card being played!
