This awesome and colourful creature is a sandworm. No, sorry, it’s not the one from Dune. We wish! 
This is a King Ragworm (Alitta virens):
An annelid worm that burrows in wet sand and mud. It is classified as a polychaete in the family Nereididae… Sandworms eat seaweed and microorganisms. They have distinctive traits, including… often reaching great length, sometimes exceeding four feet
numerous, highly vascularized parapodia [The parapodia function both as external gills (the animal’s primary respiratory surfaces), and as means of locomotion (appearing much like short legs)].

Photo by Alexander Semenov
Zoology lesson via TYWKIWDBI

This awesome and colourful creature is a sandworm. No, sorry, it’s not the one from Dune. We wish!

This is a King Ragworm (Alitta virens):

An annelid worm that burrows in wet sand and mud. It is classified as a polychaete in the family Nereididae… Sandworms eat seaweed and microorganisms. They have distinctive traits, including… 
  • often reaching great length, sometimes exceeding four feet
  • numerous, highly vascularized parapodia [The parapodia function both as external gills (the animal’s primary respiratory surfaces), and as means of locomotion (appearing much like short legs)].

Photo by Alexander Semenov

Zoology lesson via TYWKIWDBI