"Guerrilla pumpkin-carvers" made their opposition to the supermarket clear
Protesters have carved "No Tesco" in pumpkins as part of a campaign against the supermarket chain's plans to build a new store in Powys.
The action group Pumpkins Not Profits carved Halloween lanterns out of the fruit in Machynlleth.
Its members are opposed to proposals by Tesco to build a new store on the town's livestock market.
The company has said the development would offer more choice to people who have to travel long distances to shop.
Campaigners opposed to Tesco's proposals staged their protest during a parade to mark Halloween and Samhain, a Celtic festival celebrating the end of the harvest, on 1 November.
Pumpkins Not Profits said while hundreds lined the streets to enjoy the procession, a group of "guerrilla pumpkin-carvers" made their opposition to the proposed supermarket clear.
The newly-formed group said it was the perfect night to unveil their art.
A spokeswoman added: "Halloween is a time to be scared, but we're terrified of Tescos coming to town. It will likely cause the death of independent, local businesses."
In September, Machynlleth Chamber of Trade said Tesco could radically alter plans to make the town more sustainable, and negatively affect its network of small shops.
At present, some people travel about 18 miles (29km) to shop at a supermarket in Aberystwyth, even though Machynlleth has two smaller food stores.
A spokesman for Tesco said in September that there would be a period of public consultation if plans for a supermarket went ahead.
"We would like people in Machynlleth to shop at the supermarket and in the town if the plans went ahead," he added.
"The supermarket would give people, who currently have to travel to Aberystwyth to shop, more choice."