Coquina clams are so attuned to life in the foreshore that they all know exactly when to dig into the sand and exactly when to pop up.
These filmed by Margo Ross Sears in North Carolina aren't quite as choreographed, but they're way more colorful:
https://www.youtube.com/watch?v=UhtQnyH5MU0
Those cute little cockles are no match for these giant clams:
• Clams on the Beach (YouTube / halothere100)