A suspected robber shouted "this is easy, I'll be back" to frightened shop staff as he ran with a bag of cash after holding them at gunpoint, it is alleged.
Sean Kemp (25) is accused of pointing a handgun at a cashier and ordering her to fill a shopping bag with money.
Dublin District Court heard while it turned out to be a fake gun, the alleged victim had been in fear and "believed it to be the real deal."
Judge Ann Ryan refused to grant Mr Kemp bail and remanded him in custody.
The accused, with an address at a hostel at Basin View, James' Street in the south inner city, is charged with robbery at Applegreen service station, Tyrconnell Road, Inchicore on October 30.
Detective Garda Colm Reynolds told the court the accused was charged at Kilmainham station and replied after caution: "I'm sorry to that woman."
Objecting to bail, he cited the seriousness of the charge.
He said a lone male entered the service station at 9.10am with a hood up and a mask and gloves.
He approached the counter, took a black handgun from the front of his trousers and shouted at staff, demanding cash.
He pointed the gun at the female staff member under the perspex screen, handed her a blue reusable shopping bag and demanded that she put all the notes from the till in it, Det Gda Reynolds said.
He got €480 and fled.
Det Gda Reynolds said as he was running out the front door, it was alleged the accused shouted: "This is easy, I'll be back."
An "extensive investigation" followed and gardaí "tracked" Mr Kemp on CCTV from the Bernard Curtis House flats complex to the scene that morning.
The garda said the accused made admissions in interview and said he had been "drinking vodka and taking heroin."
He said Mr Kemp told them where the gun was and gardaí recovered it.
It "appeared to be a pellet gun" but an examination had not been completed.
Defence solicitor Daniel Hanahoe said it was a "plastic, toy gun" that was recovered, it was not something that required a licence and the accused had bought it in a market.
Det Gda Reynolds replied that he believed it was an Airsoft pellet gun, but it was "certainly not a toy." The shop worker had been in fear and said in her statement "I believed it to be the real deal," he said.
Applying for bail, Mr Hanahoe said the accused had a place to live and his partner was in court.
Judge Ryan said the accused was presumed innocent but having considered the submissions, she refused bail and remanded him in custody to appear in Cloverhill District Court on November 17.