Adventurers needed to clear floor 25

The adventurers navigated a labyrinth to a difficult boss in Aincrad (SAO world) . The boss was a powerful 2 headed giant that warrior mage that had 3 stages. The first stage they had few problems and could mostly outheal the damage however they had some more issues the second stage when it created a poisonous fog in the room draining int and health. Link lost his ability to do mental actions temporarily and went into voidling form (I think it was that one). most people spent a round recasting spells after they went down then went back to DPSing the boss down, after a hard fought battle it went into its 3rd stage that just started breathweaponing them causing most people to almost die. On condition of death the boss had an item of mass magic mutate and everyone in the room had to make a 6 die pwr check or receive the mutate. They identified the spell but didn't know what it was so they correctly all did their best to resist including link stressing stat. Unfortunately no one received damaged to sunlight 3.