A passerby found a 20-inch-long yellow-bellied sea snake on a beach in California, marking the third time the rare, venomous snake has been found washed up on a Southern California beach.

Lifeguards in Coronado found the snake and put it in a bucket, but it died shortly afterward. Two other snakes of the same species were found on Southern California shores, one 27 inches long found on Huntington Beach last month, and one that was about 24 inches long in Ventura County back in October. All three of the snakes have died, according to a Los Angeles Times report.

Scientists aren’t sure why this is happening, but as with most unusual phenomena like this, El Nino appears to be a prime suspect. After all, the first time Pelamis platura was spotted in Southern California was back in 1972, also an El Nino year.

These rare snakes may be trying to head north of their normal tropical habitats due to the unusually warm temperatures with a strong El Nino this year.

Although highly venomous, there are no recorded fatal bites from a yellow-bellied sea snake on a human. Compared to land-based serpents, these sea snakes have tiny fangs and can’t open their mouths nearly as wide, meaning it would be tough to get yourself bitten by one even if you tried.

The snake is characterized by its bright yellow underside and a paddle-like tail that allows it to swim effortlessly in the water. It is typically found in tropical waters — in this case the individual snake was most likely used to the waters of Central America and Mexico.