Story related, unmissable.
Defeat the S-03 boss in Chapter 11: If This Be My Destiny to unlock this trophy.
You will be teamed up with the Lizard during this battle. Defeat the sentries, and then help the Lizard open the door using the button. Repeat this twice and Smythe will join the battle himself.
Web up Smythe with whilst evading his laser beam attacks, either by jumping or web swinging away from him. Press when Smythe glows red, and you will web strike him to the Lizard, who will pull off his laser arms. Simply repeat this three times, and Smythe will be defeated, and the boss battle will be over. Much simpler than the S-02, if you ask me.