Spider-Man: When does the villain “initiate” an attack against Spider-Man?

An attack is “initiated” the moment the game determines an attack will be made against a character. This includes attacks made from game steps (such as step 2 of the villain phase) and card abilities (such as an attack initiated by the “Assault” treachery). Spider Man’s ability resolves before any of the steps of the process detailed in the “Enemy Attacks” section are performed.

-Official FAQ (1.1)