Fourteen golden heads from an art installation at Suffolk's Latitude Festival have been stolen.
The painted plaster heads, weighing as much as 15kg (33lb), were taken on Monday after the festival had closed.
South-east London-based creators Sam Wyer and Laura Drake Chambers said they were "gutted" and appealed for their return.
Suffolk Police confirmed they were investigating the theft.
The heads, worth about £5,000, were part of a group of 21 installed in the Faraway Forest at the Southwold festival as part of an exhibition entitled "For Richer, For Poorer, For Better, For Worse".
The theft was discovered when the two artists arrived to disassemble the work.
"We worked really hard to create this, and everything was secure and really respected throughout the weekend," Mr Wyer said.
'Heads on a train'
The disappearance happened after the public had left the site, he said.
"Whoever took them methodically removed them with an electric screwdriver.
"They were staked into the ground and screwed and bolted."
He said he and his Brockley-based co-creator "just want to get them back" as they are intended to be displayed elsewhere.
Ms Drake Chambers said: "Latitude looked after our installations brilliantly all the way through the festival and their support was impeccable."
Suffolk Police said they had received a report of a group of people loading heads into a van.
"We've also had witnesses saying they had seen some of our heads being cradled in people's arms on a train from Ipswich to London," Mr Wyer said.
"If that's the case we're hopeful that people took them because they thought they were beautiful and will find it in their hearts to return them to us."
The pair have started a #GoldenHeadHunt campaign on social media to raise awareness of the hunt for the missing heads.