You know how the spider kind of gets angry and puts up his front legs? As soon as he comes done, hit him with a regular attack. He will then drop down spiders. Kill them by using a stomp attack on them and then use it on them again. Keep repeating this to the big spider and the small spiiders. I have not yet killed it so I do not know what will happen at/near the end.

Once you have killed the spider it will turn onto its back then u use that by jumping on and lifting u upto where u need to go