This is not actually a ghost story but a true story that happened to my mum that I reckon is pretty scary!
Mum was a nurse and used to work in Hamilton Base Hospital, Victoria. One afternoon shift they were extremely busy and didn't have time to deal immediately with a patient who'd passed away. Some hours after his death he was laid out on a trolley and mum was asked to wheel him to the morgue. The morgue was a separate brick building that you reached by a dark alley that was not used often. By now it was nighttime, and despite being a nurse and used to death, mum said she was feeling a bit unnerved. As she she reached the morgue suddenly the dead patient slowly began to sit up, the sheet still draped over his head. Needless to say it scared the s**t out of mum.
And no, he hadn't come back from the dead, it turned out that when he'd passed away he'd been sitting up in bed, and it'd taken enough time that rigor mortis had begun to set in. Even though he'd been straightened out enough to be laid out on a trolley, the muscle contractions were enough to ensure he returned to his upright position some minutes later.
Mum can laugh about it now, but I know if it had been me it would have sent me into a dead faint there and then!