A super-sized slithering serpent that sidled up to an unsuspecting family may not be the only secretive snake concealed in the sleepy seaside town.
Experts think the reptile - which emerged from a drain in the back garden of the Peck family - may have hatched from a nest of eggs.
The snake was identified as a Mexican King Snake - hardly native to the Cleethorpes and Grimsby area.
Linda Peck told the Grimsby Telegraph: "My husband Geoff and I walked past our back door, which is made of glass, and saw what looked like a very large slug on the drain.
"It began to come out of the drain and towards the house. I was terrified – there was a big black snake coming out of a drain towards us!
"Simon tried to pick it up but it snapped at him so he put a recycling box on top of it."
Mr Peck then took the unwelcome guest to a local snake shop, Medusa's Reptiles.
Owner, Charlotte Marshall, said: "This guy came running in saying there was a big snake in the garden and could we help. As he described it, we knew straight away it was a Mexican King Snake.
"We picked up a plastic container and a stick and went to the house. The snake looked quite skinny, like it hadn't eaten in a while.
"They are quite common as pets because they are easy to look after. It was very young, so either someone has bought it recently or a female snake has escaped a few months ago and has laid eggs."