A Kent father spent three weeks in hospital after being bitten by what he believes was a false widow spider while sleeping in his bed.
Brian Smith, 43, from Maidstone, suffered severe swelling as venom spread through his body, causing his limbs to balloon dangerously.
Four months after the incident, the scaffolder is still experiencing health complications including arthritis and mobility issues.
Doctors told the father-of-three his hand could have "exploded" due to the extreme swelling caused by the spider's venom.
Smith recalled waking up to "a really sharp pain" on his right hand during the night.
Brian Smith, 43, from Maidstone, suffered severe swelling as venom spread through his body - and was rushed to Maidstone Hospital
MAIDSTONE AND TUNBRIDGE WELLS NHS TRUST
The false widow is Britain's only native species of venomous spider (file photo)
PA
The next morning, Smith struggled to move his hand - and noticed two small fang marks (file photo)
GETTY
Following his ordeal, Brian now takes extra precautions in his bedroom.
"When I was in hospital, my parents fumigated my bedroom and tried looking for the spider but they couldn't find it," he said.
"I was quite shocked a spider in the UK could cause this sort of damage. I thought this only happened in Australia and places like that."
The false widow is Britain's only native species of venomous spider - and now, Smith has urged others to stay vigilant.
"Now I always check my bed sheets. I'd tell other people to be very wary of them because they can do a lot of damage," he said.
"I'm slowly getting better but I'm still not 100 per cent."