Tidepool Tim says,  “Shimmys do exactly as their name implies - they shimmy!  These worms seem to prefer to be in the top 4" of the mud flat.  Once you expose them to daylight with your digging fork they freak out!!! They wiggle, they jiggle, they twist and turn and race all around the mud-pile.  Shimmy worms resemble a small sandworm, but their color is golden brown rather than metallic orange or green. They do have a proboscis like a sandworm that they will evert if really stressed - never been bit by one though.   They eat molluscs, crustaceans, and other polycheates.”