The Black Widow spider is one of the most venomous spiders in North America - but they don't usually turn up in Norfolk.
However, a female Black Widow has been discovered at a business near Great Yarmouth - along with a small cocoon, which produced about a hundred spiderlings just hours later.
ITV News reports that staff managed to trap the spider under a glass, before pest control teams arrived and quickly realised that it was a Black Widow.
It is believed that the spider hitched a ride on a container from Texas.
Jon Blake, director of Abate Pest Management, who dealt with the spider, told ITV: "Black Widows are very notorious spiders identified by the coloured, hourglass-shaped mark on their abdomens.
"We have been called out for snakes, scorpions and spiders before but never in the past 24 years for one of these deadly creatures."
Black Widow spiders are much feared because their bite is 15 times stronger tan a rattlesnake's. In humans, bites cause muscle aches, nausea and a paralysis of the diaphragm that can make breathing difficult.
Most people who are bitten suffer no serious long-term effects. However, bites can be fatal - usually to children, the elderly or the infirm.
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