It took three men to lift the huge Burmese python.
Vets were alerted after the reptile was clocked by guests at Monkton Wyld Holiday Park in West Dorset.
Local Peter Bacon said: “It was humongous.
“I stopped my van and took a picture to show my wife and put on Facebook in case someone recognised it.”
Expert Simon Prentice was notified of the discovery by vets.
He said: “At first I thought it was a hoax, or someone was exaggerating the size but it was 14ft.”
Simon, who runs a specialist reptile shop in Ilton, Somerset, added: “It weighs a ton and it took three of us to lift it into the van.”
He said a previous owner recognised the female python, telling him they sold it during lockdown.
It was thought that the non-venomous snake was dumped by its owner because of the cost of feeding it, or it managed to escape.
Simon, who plans to keep it, is raising funds for an enclosure.