In the below video a seasnake catches a moray eel at Giant Clam, Puerto Galera, Mindoro, Philippines. I believe the eel is a fimbriated moray, Gymnothorax fimbriatus which can reach lengths of of about 2.5 feet and apparently can make a fetching design for a dress. The sea snake appears to be the banded sea krait, Laticauda colubrina. Females can reach lengths of 4.5 feet.
Wait for the M. Night Shyamalan twist ending.