Couple find mysterious sea creatures on Boca Raton beach

Have you heard of blue dragon sea slugs?

PEMBROKE PARK, Fla. – A man and his girlfriend were out for a stroll Saturday collecting shells on the beach in Boca Raton when they came across some mysterious creatures in the sand.

It turns out that what David Marcoe and his girlfriend bore witness to at Red Reef Park was a rare sighting of blue dragon sea slugs.

So just what are blue dragon sea slugs? Well, their formal name is glaucus atlanticus.

According to the Encyclopedia of Life, this seemingly harmless sea creature is "not nearly as innocent as it seems."

The blue-tinted predators float upside down on the surface of the ocean, serving as the perfect disguise to hide from other unsuspecting sea creatures that will become their prey. Among their favorite targets is the Portuguese man-of-war. 

Although a sting by a Portuguese man-of-war can be painful to people, it's feckless to these sea slugs. In fact, these sea slugs can actually swallow their prey's stinging cells and store the poison inside to defend themselves against other predators lurking in the deep blue ocean. Yikes!

Marcoe and his girlfriend were so enamored by the species that they returned to the beach later in the day just to get a closer look at them.

Luckily, Marcoe took cellphone video of them for all those who can't go frolicking on the beach to see.