Milton Keynes' famous concrete cows could be permanently moved after recent vandalism turned them into skeletons.
The three cows and calves in Bancroft were painted as skeletons overnight last week, The Parks Trust, the charity which maintains them, said.
The charity said it was going to cost £2,000 to repaint the sculptures and in the long-term believed they might have to be moved if the vandalism continued.
A spokeswoman said it had reported the recent damage to the police.
The cows were made in 1978 as a leaving present from the Milton Keynes Development Corporation - which oversaw the building of the "new town" - and The Parks Trust was put in charge of maintaining them.
Since they arrived they have been stolen, beheaded, painted pink and had pyjamas and "BSE" painted on them.
'Respect the art'
Bryony Serginson, The Parks Trust's head of community engagement, said: "We'd rather they stayed where they were - that's where they live and people see them and associate them with that particular park.
"But in the long term if they do continue to be vandalised, then we might have to consider that.
"We are taking it seriously as an act of vandalism. It's going to be costly to us to get the cows back into the proper state that they should be in.
"We want people to respect the pieces of art for what they are."
Ms Serginson said she did not think the cows were specifically targeted due to Halloween as the dinosaur sculpture on Peartree Bridge was also painted as a skeleton in July.
Milton Keynes resident Fiona Norrie said: "I don't know if I should be angry, because they've done a really good job. It's very detailed.
"We don't condone graffiti obviously, but it's pretty awesome. It's art."