The sea spider looks similar to a sea urchin, and in "Patty Hype" they are small and far less menacing. In "Patrick's Coupon", look very similar to real spiders with a grayish body and red eyes. The spider's legs are hairy and extended to suit the body. They also have a gland on their abdomen to spin out webs.
Sea spiders have monstrous teeth and eight compound eyes.
Role in episodes
When Spongebob's Pretty Patties establishment takes off, the Krusty Krab became overrun with spider webs. One spider is seen hanging down and crying while watching a sad movie with Mr. Krabs. When Mr. Krabs is distracted by the news interruption of the hype of the Pretty Patties, the spider steals his popcorn.
The sea spider fights with Patrick at the beginning of the episode. Patrick attempts to use his sofa chair as a self-defense weapon, but it disintegrates into sand. Patrick then backs up before ending up in a spider web. He tries to free himself to no avail. The sea spider crawls down and Patrick attempts to blow it away, but the sea spider crawls onto him, shoots its web onto Patrick's eye and traps him in a cocoon. The sea spider then cuts the web and Patrick falls to the floor, finding his lost ice cream coupon in the process.
Patrick then directly speaks to the spider, parting ways with it to go out to buy himself some ice cream.