Pork chop
This is one of Karl's more ridiculous stories that he read 'on some site' on the internet. It begins when he, Ricky and Steve are discussing doctors, and Karl gives this as one of the reasons he doesn't trust them...
An old woman visits her GP for a routine check up, as she's getting on a bit, and just wants to make sure she's okay. The doctor asks her to undress and gives her an 'all over' check and pronounces her in perfect health. However, as she turns her back to get dressed the doctor says "Oh God!". The lady asks what's wrong and the doctor says " There's a lump...a tumour on your buttock..." and so the doctor immediately schedules the old woman for an operation. The operation goes ahead a few days later, and the surgeons find out that the tumour is not in fact a tumour, but... a pork chop. Apparently she sat on one five years ago, and it got stuck to her.
To which Ricky replies "I'm leaving, I'm never doin' this show again. THIS WOMAN HAD A PORK CHOP STUCK TO HER ARSE FOR 5 YEARS! OF COURSE SHE DIDN'T, YOU MENTAL CASE!"