For those living on America's East Coast, the Atlantic jackknife clam is a common sight (it's also considered a delicacy). But to the rest of us, it’s just plain weird. 

Clam Gif 2016 04 10

Named for its shell's sharp edge, and for its resemblance to an old-fashioned straight-edge razor, the clam (Ensis directus) is one of the strangest molluscs you’re likely to come across. The crazy critters can be found where land meets sea: the intertidal zone. The largest members of their genus, the clams can reach upwards of seven inches in length! 

The animals look weird enough just lying in the surf, but as you can see in this video, things get even more bizarre when it's time to move or burrow into the sand. The clam gets around by rapidly opening and closing its shell, expelling a jet of water, which propels it along. When it feels like disappearing, it uses a foot-like muscle to dig its way down into the sand, eventually ending up in a vertical position:  


Top header image: Martin Broek, Flickr