See text Pholadidae, known as piddocks or angelwings, are a family of bivalve molluscs similar to a clam.

Piddocks are unique in that each side of their shells is divided into 2 or 3 separate sections.

Furthermore, one of the piddock's shells has a set of ridges or "teeth", which they use to grind away at clay or soft rock and create tubular burrows.

The shape of these burrows is due to the rotating motion of the piddock as it grinds the rock to make its home.

The piddock stays in the burrow it digs for the entirety of its eight-year lifespan, with only its siphon exposed to take in water that it filters for food.