Such good fun to watch. I came here to say the armour was the deciding factor.
It split the incoming damage in two directions. Imagine if Crustacean King had even one armour.
It would've taken 3 hits by feral spirit to bump him off, not 2. In that time, his group heal would've helped a tonne, and kept the Mischievous Mermaid in the game a little longer.
@mys is spot on.