With its horns, long white body and slithery form, it looks like a mythical beast.
But this four-metre long horned creature is only too real - as the stench from its decomposing flesh proved.
The mysterious sea creature was washed ashore in Villaricos, Spain - and tests are being done on the carcass to determine what it is.
The four-metres long creature, seen with its head detached from its body, is in an advanced state of decomposition
A swimmer stumbled across the horn head and decayed body on a Spanish beach
An unfortunate swimmer stumbled across the head before coming across the rest of the body, the Huffington Post reported.
Civil Protection Coordinator Maria Sanchez said: 'We have no idea what it can be, but it smelled bad, because it was so badly decomposed', Digital Spy reported.
She added: 'A lady found one part, and we helped her retrieve the rest… We have no idea what it was. It really stank, as it was in the advanced stages of decomposition,' Inquisitr reported.
The extent of the deterioration of the creature meant most of the remains had to be buried for safety reasons.
Several theories have been suggested about what the creature is - ranging from it being a type of shark to it being an oar fish, but researchers are still examining it.
Programa en Defensa de la Fauna Marina (PROMAR) spokesman Paco Toledano was also puzzled, Yahoo reported.
Several theories have been suggested about what the creature is - ranging from it being a type of shark to it being an oar fish
He said: 'It's hard to know what we’re dealing with,' Mr Toldano told ideal.es.
'It is broken up and we can not identify what ii is. Maybe it's a bull fish', he joked.
'Perhaps if we were able to analyse the bones we might know more, but for this specific genetic analysis it is very expensive and who would pay?
'We've certainly never before seen anything like this.'
A spokesman for the Marine Biological Association said: 'A few people have said it could be the backbone of a shark with the rest of it decaying away.
'Really we would need a vertebrae to properly identify it. If it was a shark it would have cartilage skeleton as opposed to bone.
'As for the horns - it's pretty inconclusive. No one knows of anything with horns in the sea. From the picture you wonder if it is even part of the creature.'