A woman claimed to find a maggot "wriggling around" on the top of a luxury Gu chocolate dessert.
India, aged 27, bought the melt-in-the-middle puddings from a Sainsbury's in Clifton Down, Bristol, on October 3.
Looking forward to tucking her treat, India was instead "horrified" to find a live maggot on top of one of the puddings, Bristol Live reports.
A video, recorded by India, shows a little yellow maggot crawling on the surface of the chocolate sponge.
It's a mystery as to how it got there, but it looks very much alive.
The unhappy customer emailed the luxury dessert brand and said she was offered vouchers as compensation.
"I was pretty horrified to open the box and see a maggot wriggling around on top of one of the puddings," she told the title.
"I'm not sure if the maggot got in the box at the Gu factory or during the transportation stage, but it's not good enough regardless of when it happened in my opinion.
"You don't expect this kind of thing from any company, but especially not one like Gu which is known for its quality.
"After finding the maggot I chucked both puddings in the bin. It's a shame because I love Gu's puddings, but I'm not sure I can bring myself to buy one again after this."
India said she contacted Gu the same night she bought the puddings.
The company responded to her on October 5, she said, asking her to send it the maggot in the post – but she had already thrown it away along with the puddings.
"As I didn't have the maggot to send to them they said they can't continue the investigation, but they were very polite in their email response to me and offered me some vouchers," she added.
"Let's hope it was just a one-off freak incident."
Gu said complaints of this nature are "extremely rare indeed".
A Gu spokesperson said: "We were very sorry to hear that one of our loyal consumers’ experience didn’t live up to our high standards.
"We have stringent quality checks and processes in place to prevent incidents like this and we can assure you that complaints of this nature are extremely rare indeed.
"Moreover, we take all complaints very seriously and strive to learn and improve from each and every one.
"We are working closely with her and this complaint is being thoroughly investigated by our team."
A Sainsbury’s spokesperson added: "We are in contact with India and are investigating with Gu."