Pensioner Patricia Seagroatt had the shock of her life after she went for a morning stroll - and came eye to eye with a lynx-like cat the size of a labrador.
The 67-year-old claims to have seen the beast as it hunted a wood pigeon on scrap land in West Mersea Esplanade.
She said she was so "gobsmacked" by the sight she did a double take before going back to the safety of her home to call police.
Mrs Seagroatt, who has lived on the island for 13 years, said: "I was flabbergasted. I didn't know what to do so I called the police and they said I did the right thing."
The cat was spotted on Wednesday morning as Mrs Seagroatt walked past a row of houses.
She said: "I noticed something out of the corner of my eye and looked and thought that's not a fox, it's too big'.
"It was big and looked like a lynx. It just sat there, then it tried to catch a wood pigeon in a bush. I thought about knocking on the door of the house next to where I saw it because I was worried they might have cats.
"I have never seen anything like it before. It had really muscular back legs and dark feathery stripes on its hind legs.
"I never felt threatened. I think it was probably more nervous of me than I was of it."
Mrs Seagroatt is the latest in a long line of people who claim to have seen big cats in Essex over the last decade.
The sightings were becoming so regular some locals have become convinced there is a Beast of Essex.
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