Dad-of-two Jon Hughes had his stomach turned - after finding a dead shrew in his packet of crisps.
Jon, 44, had already eaten half the packed of Kettle Chips before making the revolting find.
The coffee shop owner, from Conwy, North Wales, bought the large bag from Sainsbury's, to split with wife Elinor.
Jon said: ‘I felt utterly disgusted when I saw it. It's such a horrifying discovery.
‘Me and Elinor had tucked into them completely unaware, and were just about to give them to my son for his packed lunch.
‘It's so gross and a real breach of food standards. I still feel sick and will never be eating a pack of crisps again.
‘Also just because it's a shrew and not a mouse, does not make it okay.
‘Following their investigations, Kettle Foods have just said it's a 'mystery'. But that doesn't explain how it's crawled into an airtight bag and sealed itself in.
‘The bag was delivered completely untampered with.’
Jon immediately contacted Kettle Foods UK to complain about the grim discovery, and was asked to send over a picture of the 'foreign body' to back up his claim before posting it to them.
But just a minute after doing so, the company phoned back saying they were sending a courier around to collect the rodent.
A spokesman for Kettle Foods UK admitted they had launched an investigation into the problem.
A Kettle Foods UK representative said: ‘We take food safety and quality very seriously and have stringent systems and procedures in place to ensure that every bag of our crisps reaches our consumers in perfect condition.
‘We have been in dialogue with Jon Hughes and will respond fully to him as soon as we have completed a full investigation, including all appropriate lab tests.
‘This work is ongoing now and we expect to be able to provide an update to them later today. Kettle Foods prides itself on making quality products.’