OK, that's messed up.
What's even more messed up is that she was about to feed the grapes to her young grandchildren when she spotted the orange and black Chilean spider.
63-year-old Gillian Shivers said that she'd just opened the carton of grapes when the 8cm (3in) arachnid crawled out of the middle 'like the stuff of nightmares'.
As you can probably imagine, she was pretty shaken up by this. She screamed for her husband, 69-year-old Tony, who killed the spider by pouring boiling water on it.
I mean, obviously no-one wants to find a spider in their grapes, but what a way to go, eh?
After they'd brutally killed the spider - who, let's face it, probably wasn't keen on being there either - they put it in a plastic tub.
Somehow the spider had made it all the way from South America to Newark, Nottinghamshire. It's not clear how, but that's some effort on the spider's behalf.
Gillian and Tony's daughter Helen then took the spider and the grapes back to the supermarket that they'd bought them from and demanded an explanation.
Helen said: "She got the shock of her life that's for sure. She said it was the stuff of nightmares.
"My mum usually buys the grapes and washes them before giving them to my kids but as she went to do so it just crawled out towards her from the centre of the bunch.
"These things can shoot spikes and are venomous. It may not be able to kill people but it could give a nasty bite so her first concern was for her grandchildren.
"She screamed for my dad and he came down and poured boiling water on it. People have criticised us for killing it - but imagine being faced with a live tarantula in your grapes.
"They say they are only aggressive if threatened but I think it probably would have felt pretty threatened after being hauled up in a box of grapes for God knows how many days and travelling that far."
She continued: "It was amazing that it survived the journey, it would have been in fridges between 0-5 degrees. Apparently they don't hang around fruit either, so it's pretty unusual.
"I took it back to the store and at first they didn't seem that bothered, they just said 'oh we get spiders in fruit such as bananas all the time'.
"I said 'but this is a bloody tarantula'. They have now taken the spider back and launched an investigation.
"It's not something you see every day and certainly gave my mum a shock to say the least."
Since the incident, the spider has been identified as a baby mygalomorph tarantula. It's usually found in Chile. That's according to Dr Sara Goodacre from the University of Nottingham's School of Life Sciences.
A spokesperson from the RSPCA offered some advice on what to do if you find a strange creature in your grapes.
They said: "The RSPCA receives a number of calls every year after members of the public return home from holiday or buy fruit from the shops to find a stowaway spider, lizard or scorpion on board.
"While they are concerned for the welfare of these animals, as they're not native to this country and may well have faced an extremely long and arduous journey, the RSPCA would always advise people to treat any unidentified animal with caution until identified accurately, and not to handle an animal that has been discovered as accidentally imported."
Aye, but probably don't pour a load of boiling water on it, either.
Morrisons has been approached for comment.
Featured Image Credit: SWNS