Tube worms are a kind of creature that live deep in the ocean. They have long, tube-like bodies and survive by feeding on chemicals from underwater vents. Full definition
In the rock record, they stand out as very unusual features that have this strange spaghetti - like appearance related to fossil tube worms and an abundance of other fossils. (sciencedaily.com)
As for an actual timeline for those first tube worms, if they exist, it's still very, very early days. (extremetech.com)
Some deep - sea tube worms get long in the tooth... er, tube. (sciencenews.org)