It is a large, dark green and light green snake with red eyes and big fang-like teeth. It has been shown to eat what would be indigestible objects to humans.
It appears to be hostile towards individuals who enter the sewers it dwells in, as demonstrated with SpongeBob and Squidward in the sewers.
Role in episode
The snake is first seen in the sewers where it pops out of the water and lifts the safe, containing the Krabby Patty secret formula, with its nose. The snake then acts aggressive towards SpongeBob and Squidward and chases them through the sewers where it eventually ears them. However, by tickling the inside of its stomach, SpongeBob and Squidward successfully make the Sewer Snake vomit both of them out of its mouth.