The feathered fiend was caught on camera making its way on foot through the doors of the Belmont Filmhouse before parading in front of unsuspecting box office workers.
But it caught them off guard when it suddenly launched itself at them before flying off towards the exit.
The three men, who chased after the bird as it made its escape, were left in a flap after the incident on Friday, according to their colleague Calum Scott.
He said: “The guys who had been working in the ticketing booth looked genuinely traumatised by the whole episode.
“They didn’t know the gull was there until it was flapping in their faces.
“Until I saw the CCTV footage, I didn’t quite believe them.”
Mr Scott added: “We’ve all seen gulls in Aberdeen stealing food from people and causing a nuisance.
“But I don’t think anyone expects them to actually come inside a building.
“I really don’t know what it was looking for - food I guess. But in the CCTV footage you can see it’s walking around as if it owns the place.
“We all found the whole thing really funny, but it’s also unbelievable just how bold the gulls are becoming.”
Gulls in the North-east have proved a tough lot to scare away in the past - despite many efforts.
Residents regularly complain about the bold birds pinching food from passers-by and dive-bombing built-up areas for scraps.
The local authority has spent nearly £200,000 in the last five years trying to combat the pests.
Belmont Filmhouse cinema manager, Colin Farquhar, said that the aggressive seagull had frightened staff member Jack Morrison so much that he let out a scream when the bird flapped in his face.
Mr Farquhar said: “There was one member of staff in the ticket booth, and another member of staff who was about to clock-off was having a yap with him.
“Ian Cushnie, our duty manager was coming up the stairs when one of the guys in the box office let out a scream or cry for help as a boisterous Aberdeen seagull approached them.
“I can only describe it as a harrowing escapade.”
He added: “We’ve got a customer who regularly gives us doughnuts so I’m wondering if there was some kind of treat behind the box office that he was looking for.”