MYRTLE. BEACH, S.C. (WBTW) — Springtime along the beach means many changes for sea animals, including the hooked jaw clamworms recently seen popping up in swarms.

The animals, which ordinarily live on the seafloor, undergo reproductive transformations during the full and new moons in the spring, according to the state Department of Natural Resources.

If you see a frenzy of these marine worms, stay clear. They have a mouth, a lip, two pairs of eyes, and a set of strong hook-like jaws, according to enature.com. Unlike an earthworm, the clamworm’s mouth and jaws are strong enough to break human skin.

In the springtime, their bodies morph into reproductive forms called ‘epitokes’ as they swarm in coastal waters. This phenomenon occurs every year and is often followed by hungry throngs of fish and birds along the marsh edge, according to the SCDNR.

“You may not want to go swimming with epitokes, as clamworms do have a set of hooked jaws, but it’s hard not to appreciate such an unusual coastal sight,” SCNDR staff posted on social media.

Clamworms are not only tiny creatures. They can grow up to 36 inches long and one and three-fourths wide, say folks at enature.com.