A holidaymaker who caught and ate an octopus was "horrified" to learn it was only the second rare six-legged specimen ever found.
Mechanical engineer Labros Hydras, 49, pulled the creature - dubbed a 'hexapus' - from the sea as he went snorkelling in Greece.
He followed local tradition by smashing it against a rock to kill it and then took it to a nearby taverna to cook.
Labros Hydras cooked the octopus himself after a local chef refused
The chef refused to cook it for him because it was so rare and told Hydros he should have let the octopus live.
But the hungry father-of-two went and fried it for his supper anyway and served it up with a slice of tomato, lemon and a solitary salad leaf.
After finishing it off he decided to check out what the chef had said - and felt sick when he realised what he had done.
The six-legged hexapus had been unheard of until five years ago when one nicknamed Henry was found off the North Wales coast.
That first-ever recorded discovery was taken to Blackpool Sea Life Centre before being released back into the sea.
Repentant Hydros, 49, a US citizen living in Washington DC, is now helping sealife experts in Greece with what he can remember of the catch on Papa Nero beach on Pelion peninsula.
Hydros, who was snorkelling with daughter Areti, ten, and son Arion, six, said: "It tasted just like a normal octopus but now I feel really bad.
"When we caught it, there was nothing to suggest it was any different or had been damaged.
"I thought it had just been born with six tentacles. We go to Greece every year and when we catch an octopus we do the same thing so we just did not think about it."
He added: "I wanted to find out more, but there was no internet where we were.
"I then called my friend who is a biologist and he told me it was true and I was horrified. Now I want to pursue the scientific angle to make scientists aware of the existence of the wild hexapus.
"It is the least that I can do given my ignorance and guilt that I feel for killing such a rare animal."
Hydros and his children examine the find on Greece's Papa Nero beach, on the Pelion peninsula
Hydros, who was born in Greece but is now a US citizen, has shown his evidence to specialists at the Hellenic Centre for Marine Research in Greece.
He said: "I will pursue the scientific angle though to make scientists aware of the existence of the wild hexapus.
"It is the least that I can do given my ignorance and guilt that I feel for killing such a rare animal."
Biologists say the six-legged hexapus is the result of a pre-natal abnormality as opposed to a new species.