Two robbers wearing Halloween outfits smashed their way into a Fontwell petrol station and stole the safe.
The two men went to the Shell Service Station in Arundel Road, Fontwell, at 1.20am on Sunday, October 30.
The cashier heard a loud crash and was confronted by a man wearing a skeleton costume armed with a baseball bat.
Police believe he and his accomplice had used a concrete bollard to smash the locked front glass door.
He shouted at the cashier and the other man jumped over the counter and grabbed a safe containing cash.
The men then got into a three-door silver vehicle and made off towards Bognor Regis.
The male staff member was unharmed but left shaken.
The robbers are described as wearing all in one skeleton costumes with attached hoods which covered their faces. Both were of medium build and about 5ft 8ins.
Anyone who saw anyone acting suspiciously in the area or driving in the silver vehicle should contact Sussex Police on 0845 60 70 999 quoting serial 0274 of 30/10.