A Doomed Pilgrim in the Ruins of the Future

The rock is shaking. Realizing it's been spotted, it picks itself up revealing itself to be a rather tall rock-like spider. It begins laughing openly having been revealed.
Slowly, more small spiders of all shapes and colors begin to crawl out of the hole left behind by the large rock spider. Each one of them is giggling eerily.

Woah.
I backpedal through the sand. I'm unarmed - but it's not as though I could fend a swarm of spiders off with a sword, in any case. My situation looks pretty desperate! What does the giant spider want with me? Or can I even tell?
Anyone should answer.