The boss is (I think)
Coral-fueled SEA SPIDER
What loadout did you use?
I used
Plasma blade and pilebunker left hand. Laser rifle and vertical missile launcher right side. Reverse joint feets.
I feel I did not "get" this boss. The only reason I was able to win was because pilebunker charged damage output was insane. Everything else felt like it was tickling the guy.
The first time I went against it I had a tetrapod with laser cannons and gatling guns, which ate absolute shit and couldn't move fast enough to escape the stomps. Then I came back with a lightweight reverse joint with a shotgun, pile bunker, and whatever missiles fit after that and casually rolled over it first try by just being hyper aggressive and sticking to it.