RALEIGH, N.C. -- A slimy, pulsating creature caught on tape by a robotic camera patrolling Raleigh's sewers has sparked curiosity and horror on YouTube and other Internet video sites.

A Raleigh public utilities spokesman says the creatures, dubbed "sewer monsters," were recorded in privately owned sewer lines below the Cameron Village shopping center.

The News & Observer of Raleigh reports that the monster is actually a writhing mass of thousands of tiny organisms called bryozoans.

A North Carolina State University biologist said the worms bunch together and feed with tentacles. They can grow as large as a watermelon.

The infestation of worms poses a hazard because it can create blockages in the sewer system.