Social media users were left amazed after a “Spanish dancer”, an enigmatic sea creature, was sighted on a beach in Australia.

The Spanish dancer was spotted at Coral Bay, Western Australia. Image credit: Adigaz/Instagram

Instagram user Adigaz captured the attention of the online community after sharing an incredible encounter with a “Spanish dancer” sea slug while walking along Coral Bay on the West Australian coast.

According to the poster, the animal was carried in by the tide at the beach. Its mesmerizing pattern and colors left social media users awestruck. But what exactly is this vibrant blob?

The interesting-looking animal captured the attention of the online community. Image credit: Adigaz/Instagram

The Spanish dancer seaslug, Hexabranchus sanguineus, is a fascinating marine creature that lives in tropical waters from Asia to Africa and South America, and has a number of interesting features. It is a large dorid nudibranch, a type of sea slug that is a gastropod, just like common garden snails and slugs, only much bigger.

The Spanish dancer is actually one of the largest of nudibranch species and can grow up to 90 cm (3 ft) in length. However, such an enormous size is quite rare, and they usually measure around 30 cm (1 ft).

Yes, the Spanish dancer is indeed a slug! Image credit: Ewout Knoester

The Spanish dancer got its name for its graceful and coordinated rhythmic movements that are reminiscent of the undulations of a Spanish flamenco dancer’s red skirt. And it can really dance!

When the Spanish dancer needs to get about in a hurry, it swims (usually when threatened). However, due to the absence of bones and significant fins, it has limited choices for movement. So it uses its mantles, which it normally holds in an inwardly curled position, to provide propulsion with an undulating movement that results in a rather meaty acceleration.

The vibrant red hue of this sea slug is not just for show. Similarly to other nudibranch, the bright color serves as a cautionary signal to potential predators of its toxic nature. The toxins come the Halichondria sponges, which are a part of the sea slug’s diet.

Despite the fact that Spanish dancers are hermaphrodites, meaning that they have both male and female reproductive organs, they do not self-fertilize, but reproduce sexually. The eggs are a red to pinkish coloration and are laid out in a distinctive rose-looking formation (and are also toxic).

The pinkish eggs of the Spanish dancer are laid out in a distinctive rose-looking formation. Image credit: Murex Resorts

These and other fascinating features make the Spanish dancer sea slug a unique and captivating species to study and it is therefore quite popular with divers.

Sources: 1, 2, 3, 4, 5, 6