[spoilers, because yu asked for it!]
I'll make it quick.
Shoot his face so that his eye gets free.
Then, light the eye with sun form charge so that it sparkles.
After that, it's vulnerable for some time so blast it with energy shots. If necessary, repeat.
At some point it will start swinging back and forth rapidly, as soon as it does that use bind to pop it out.
Then Li gets free and you can use dual form again.
Then, in the place where Li was, a face pops up that shoots a HUUUGE beam that HURTS (screen turns blue just before it does that). You'll have to hit that face with a charged up dual form beam so that it releases 3 mutilus you can kill to get scream power. The time frame is very short before that beam gets you. If you can't get the timing right, use crab cake or some other +defense food to minimize beam damage.
You will want to turn off your pat for this last fight, otherwise it may happen that it steals the kill from you and you don't get the energy to scream, so you have to wait for the beam again.
To scream i always swim up to his face to make sure it gets him
Scream 3 times and ... you win. Sort of.
Now I'm curious which ending you'll get
