The shopper knew something wasn't right the moment she opened the bag of kale and spinach she'd purchased from the supermarket less than a week earlier and smelled something "decomposing".
On further inspection, she found what she believed to be a "partially dismembered mouse" mixed in with the leaves.
Posting on Woolworths' Facebook page, she described the nasty find as "what looks like a leg, fur and partial back section of a mouse".
"This is revolting and unacceptable and we are angry how this occurred," she wrote.
"The contents of this bag claim to be 'washed and ready to use' which it obviously wasn't and we can never have faith in that claim again after this experience."
The woman went on to detail how the find had impacted her both physically and emotionally.
"We are traumatised, nauseous, sickened and rattled by this and it's not ok," she concluded.
Disturbing photos taken by the customer show a small, fleshy looking object laying next to some of the mixed leaves.
Fellow Woolies shoppers were equally shocked by the images, with many slamming the discovery as "nasty", "revolting" and "gross".
"Omg that's disgusting. Are you guys ok?" asked one person.
"We're disgusted and thankful it was found before we ate it and got sick," the customer replied.
Another Facebook user declared they would now stick to the loose mix lettuce leaves.
Woolworths investigating nasty surprise
In a statement to Yahoo News, a Woolworths spokesperson said the issue had been passed onto the retailer's supply chain partners and so far there hadn't been any "similar reports".
"As today's Fresh Food People, we take food quality and safety very seriously and are disappointed to see this customer's report," the statement reads.
"We've passed this onto our supply partners to look into further and haven't received similar reports.
"If our customers are ever concerned with the quality of our products, we encourage them to contact their local store for a replacement and refund."
Do you have a story tip? Email: firstname.lastname@example.org.