Members of the Pontesbury Congregational Church were sprucing up the gardens when Wendy Williams came across a 3ft long orange and white snake, believed to be a corn snake.
She gave it a nudge with her foot to check if it was real and not a late April Fools prank, but she received a shock when it reared its head.
Members tried to keep an eye on it and get someone to come and rescue it, but it slithered away down a hole.
Wendy said: "We had a garden fellowship where we go out and weed the garden. I was taking up some weeds to the compost and I saw an orange snake with white markings. It was about 3ft long.
"I thought it was a toy and somebody put it there as a practical joke. I went and got someone else to come and have a look. I nudged it with my foot but its head came up.
"We think it's a corn snake. I rang the RSPCA and they said if it's a native snake not to call the police. They put me in touch with the reptile people in Bournemouth. They said to ring the RSPCA to come out but I don't think they're coming."
Wendy has appealed for the owner to come forward on social media, but nobody has come forward yet.
"We don't know if it's escaped or if someone's had enough of it and let it go. We spent a good few hours down there and we're going back tomorrow to see if we can find it. The reptile expert said he didn't think it would last in the wild.
"Some people thought I was joking about it, but it's definitely not a joke."
Corn snakes are commonly kept in captivity in the UK and their diet largely consists of mice.