Jag saxar från nån av FAQarna (hihi) på
www.gamefaqs.com :
Directly above his head is a tail (belonging to
the dragon who resides on top of this volcano). You can grapple onto it. Do so
and swing across to the other side. This will bring the ceiling down, cracking
Gohma in the head. Gohma will fling the ceiling back up where it belongs, at
which point you can repeat the process. After hitting him three times, his
carapace is shattered, allowing you to hurt him. Lock onto his head and use the
grappling hook on it. This will pull it close enough for you to poke him in the
eye a couple times. Do that until he is dead. If you're good, it'll only take
two head grapples.