A woman has claimed she bit into a McDonald's chunky chip, only to find it was a deep fried slug instead.
"I took a wedge with a big black spot on it, I thought that must be normal, I bit into it and I felt a slimy material", Melanie, a student from Bordeaux, who asked to be identified by her first name only, told the Sud Ouest newspaper.
"I had already swallowed some, but I spat out what I could and I found that there was a slug lodged in the potato”.
After being "sick all afternoon" Melanie said she returned to the restaurant later in the day, where she showed the slug to staff, who offered a refund and a free meal.
But the student told Sud Ouest she was “unhappy” at the lack of attention she received and claimed the manager "did not respond at all".
“It's not insignificant to eat a slug while believing you are eating chips,” she said.
A McDonald's spokesperson told the Independent: “McDonald’s has taken seriously the distress expressed by this customer on Tuesday 28th March. Following our standard procedures, the restaurant immediately launched an internal investigation into the issue.
"As it stands, we suspect that the root of the issue was caused by a defect of the potato used in our fries, which is not dangerous."
It is not the first time one of the slimey creatures has turned up in fast food.
In 2015, a man from Marseille claimed to have discovered a slug in the bread of his hamburger, although McDonald's strongly denied the allegation, insisting that it was actually just a patch of flour cooked twice, which happened to be slug shaped.
That year, a ten-year-old girl from Wales said she had found a dead frog in a McDonald's wrap - a claim the fast food chain said was "unlikely" at the time.
Two years earlier a British man found a slug in the lettuce on his Burger King meal.