It's a crap life

The lot of a lugworm is not altogether a happy one. He/she spends his/her life buried in the sand or mud, confined to a U shaped burrow, eating sand or mud, digesting what little nutrient it contains, and then crapping out the residue back onto the surface. The only fun that they have, is in creating a rather splendid cast from their sandy faeces, for the delectation of the passing blipper.