The short social media video shows a selection of Dairy Milk bars and bags, limp and squished due to the chocolate inside melting.
Filmed by Alice Nadia, she said the video was taken in the B&M store at Featherstone.
The short 10 second video has been seen by more than 1.4million people and shared more than 5,000 times.
Thousands of people commented on the video and one user managed to see the sunny side, writing: "Woo that’s all going in the reduced bin. cheap chocolate for me".
It comes as the UK experiences a heatwave, with temperatures set to reach 37C in Yorkshire over the next few days.
The Met Office has warned of “a very serious situation” and issued its first red warning for extreme heat.