Those aren't treats: Sea slugs washing up at Coronado Dog Beach may not be dog safe

People are used to seeing seaweed and shells wash ashore at Coronado Dog Beach, but not the strange creatures that look like organs.

We found some people poking at the creatures with sticks Tuesday afternoon.

Others, like Ellen Govan, snapped pictures to send to people for answers.

“I’m going to send it to my nephew who's a tidepool nerd and say, ‘What is this?’" she said

We showed pictures of the peculiar castaway to Dr. Greg Rouse, a marine biologist at Scripps Institution of Oceanography. He said it's likely a sea hare, which has an internal shell or a side gill, or a sea slug with no shell.

"They don't have jaws and they wouldn't go after any people. They're strictly hunting for other little slugs and mollusks," explained  Dr. Rouse.

Lifeguards say they're seeing the creatures more often.

But why they're showing up on the Coronado's shore is a mystery.

"They might have been hit by some low oxygen that caused them to lose their grip or some kind of swell has just come in that's rolled them along," Rouse said.

The creatures are an enticing, yet potentially dangerous attraction for the many curious K9s at dog beach.

“He sniffed at it and then ran away. I said no, we're not going to eat that beach snack," Govan said.

Because a different species in New Zealand proved to be toxic, Rouse suggests caution.

“I would stay well clear from eating these sea slugs and keeping your dogs, for instance, from eating them. The local one hasn't been shown to be toxic, but I would be very careful," he said.