Found in the northern hemisphere where the water is shallow, brackish and temperate, they hide those pretty, iridescent green, blue and yellow colours in U-shaped burrows dug down into the sediment.

From here they’ll snare their prey of small worms, crustaceans and molluscs in much the same way as the dreaded bobbit worm – shooting up through their burrows to strike with their two pincer-like teeth before retreating back down to feed on their prize.

Photos by Alexander Seminov via Scientific American.