Ghoulish props from the York Dungeon - including severed limbs and a skull - have been lost during recent floods.
A replica skull is among the exhibits claimed by the flood waters
Staff at the Clifford Street tourist attraction fear the macabre items have been washed into the River Ouse and could alarm the public.
They found the exhibits were missing as they mopped up after flooding at the weekend forced the dungeon to close.
General manager Paul Brooks said: "The public could get quite a shock if they saw them floating in the Ouse."
'Macabre and shocking'
Several mannequin-style arms and legs painted with fake blood, a fake skull and even a replica medieval instrument of torture known as a tongue-tearer are among the missing props.
Mr Brooks said: "We'd obviously like to retrieve them, especially as they are of a rather macabre and shocking nature.
"I walk along the river on my way home so I'll be keeping any eye out for them."
The items were part of the York Dungeon's new Ghosts of York exhibition which was under construction when the floods hit on Friday.
Plans and sketches relating to the new feature were also ruined by the rising waters which left the room under two feet of water.
The site was forced to close on Friday, Saturday and Sunday, when it would normally have handled about 1,000 visitors. It reopened for business on Monday.
Performance supervisor Bernie Fleck said: "The flooding was pretty bad inside and we spent the weekend in waders clearing up the mess.
"We've no idea what happened to the missing limbs - they must have been washed out of the fire doors and into the river."