A YOUTH wearing a dinosaur onesie is being sought by police after he allegedly demanded cash and a phone from a man before throwing glass bottles at him.

The costumed teen was with two other youths and a teenage girl when a 21-year-old Glen Waverley man was allegedly threatened at Syndal Railway Station, on October 16 at about 3pm.

According to police, the alleged offenders followed the man off the train and through a pedestrian tunnel before one of the boys pulled grabbed his backpack and pulled him to the ground.

The victim refused to hand over his wallet and mobile phone and managed to run away with the alleged offenders throwing glass bottles toward him.

He was not injured.

Police are now on the hunt for the four young people with detectives keen to speak to anyone who witnessed the incident.

Speaking about the incident, Constable Steven Willer of the Transport Crime Investigation Unit said the outfit was unusual.

"It's fairly rare to have an offender that uniquely dressed. We don't often come across someone dressed in a costume where we can see his face and dressed like that," Constable Willer said.

He said the footage showed some of the youths carrying bottles, and didn't rule out the fact they could have been drinking.

"They do appear to be stumbling," he said.

And he said the group allegedly tried to snatch the man's phone earlier.

"Apparently on the train from Melbourne Central they were walking up and down the aisle, harassing the victim and apparently tried to snatch the victim's phone from his hand."

Constable Willer said the victim was now afraid of catching public transport and going out in public.

Anyone with information is urged to contact Crime Stoppers on 1800 333 000 or go to www.crimestoppers.com.au

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