A CALDERDALE student let out "an unearthly howl" during a phone call to his parents, moments before disappearing at a music festival, an inquest was told.
David Plunkett, 21, from Shelf, vanished after leaving the Budweiser Music Festival at the Daytona Racetrack in Trafford Park, Greater Manchester, on April 17.
His body was pulled from the Manchester Ship Canal nearly two weeks later on April 30, Stockport Coroner's Court heard.
The hearing was adjourned.
The last people to hear from David were his parents, Michael and Anne Plunkett, who called him at 1.30am on April 18 after his friend, Michael Vittis, had phoned and said they had become separated.
Mr and Mrs Plunkett told the inquest that their son sounded "spaced out" and "not really with it" when they spoke to him.
During the phone call David, a student at Leeds Metropolitan University, started to scream and howl.
Mr Plunkett, a 62-year-old probation officer, said: "It was an unearthly howl. I had never heard anything like that before.
"He was swearing and he used words I have never heard him use before."
Mrs Plunkett, a 55-year-old head teacher, said that she became worried after Michael's call and phoned David. She said: "I phoned David on his mobile. I rang three times before he responded.
"The scream was so sudden and came out of nowhere. It was as if someone had startled him. It came right out of the blue.
"That's what scared me so much. I had never heard him scream and he had never sworn in front of me before."
David's mobile phone was found by his uncle, John Copple, near to where his body was recovered, in the Manchester Ship Canal half a mile from the Daytona race track.
Home Office pathologist Dr John Rutherford said there was absolutely no evidence that David had been assaulted and that the most likely cause of death was drowning.
The inquest heard that he had "quite a lot" of alcohol in his system.
South Manchester coroner John Pollard adjourned the inquest to a later date to be fixed for additional evidence to be called.
He said he wanted further examination of safety measures in place at the event.
"I need to speak to Budweiser themselves to find out about their protocols and safety guidelines," the coroner said.