Worms are invertebrates with elongated, soft bodies. Though the earthworm is the most common, there are many varieties of worms, who in popular culture often have negative connotations, associated w/ "creepy crawlies" at worst, or with sour-flavored gummy candies at best. On Sesame Street, however, the worm is a much loved & vital species w/ an elaborate culture & society of its own.
Worms have appeared on Sesame Street as early as episode 1, in an animated segment to demonstrate the letter W. Early segments of this often referred to the worm as "yucky," feeding to the popular prejudice, & raising concerns from 1 conservationist.
For the most part, however, worms are presented in a very positive light, mostly in the person of Slimey, the pet of Oscar the Grouch of Sesame Street, NYC. Slimey is beloved by Oscar, well-liked by other residents, & proved popular w/ viewers. Later on, Slimey's family was slowly introduced, including his sister Sloppy, as well as their parents Dusty & Eartha, even their cousins Squirmy & Rachel. Other Grouches also have close relationships w/ worms. Grundgetta has Sylvia, & the participants in the Worm Summer Games each have their own Grouch trainer.
Worms have their own community, culture, & organizations, established through the labor of the worms themselves. They establish their own mass transit system in the form of a worm subway (episode 3164) & band together to build a playground (episode 3957). In addition, Slimey is a member of the Worm Scouts, a scouting troop, & all worms enjoy the annual Wormy Gras festival, the annelids' answer to Mardi Gras, & an ode to the joys of worminess.