Worm
The remains of a Falumpaset being consumed by scavenging worms.
Worms, spineless and soft, were present on various planets, including Dagobah, Ansion, Coruscant, and Naboo. Some of these species functioned as scavengers. One specific variety was the Rotworms.
Within Coruscant's undercity, enormous worms made their home, becoming the focus of a risky racing wing maneuver attempted by Anakin Skywalker. The objective was to obtain a scale from one of these worms, residing in an area notoriously hard to reach by racing wing. Skywalker, at the time a young Padawan, misjudged the distance and required rescue from these worms by his Master, Obi-Wan Kenobi.
As insult
The term "worm" also served as an insult or descriptive modifier. Darth Maul would sometimes use this word to mock opponents he considered inferior, implying they were worthy only of being associated with worms. The Jedi Exile was also known to have used the term "worms" toward her adversaries on occasion. In the moments leading up to the Battle of the Great Pit of Carkoon, Han Solo hurled the insult "slimy piece of worm-ridden filth" at Jabba the Hutt.
Lt. Bella of Sabaoth Squadron was known to berate her troops as "incompetent worms" when they failed, such as when they couldn't secure parts for an Orbital Defense Cannon. The phrase "as dirty and happy as a worm" was also a common saying.