A raider wearing an Iron Man mask kept watch outside a pawn shop while his pal went inside to rob it while armed with a toy gun.
Simon Stafford, who was disguised as the fictional superhero, and Michael Trotter, who was carrying the fake weapon, made off empty handed despite causing "terror" at the Cash in a Flash store in Washington in July 2014.
Newcastle Crown Court heard Trotter, who was also masked, had approached a father and son who were working at the store and demanded money.
When the brave workers refused, Trotter, who had downed 30 valium tablets and eight cans of lager, made threats and brandished the gun but then left without a penny.
Trotter, 29, of Binsby Gardens, Gateshead, and Stafford, 40, of Striding Edge, Washington, who did not know his friend was carrying or intended to brandish the fake gun during the raid, both admitted attempted robbery.
Trotter admitted additional charges of having an imitation firearm to cause fear of violence, a burglary at his former partner's home and possessing a small amount of cannabis found at his home.
He was jailed for a total of four years.
Stafford was cleared of the imitation firearm charge and burglary by a jury but admitted possessing a small amount of amphetamine found at his home.
He was sentenced to 18 months behind bars, which he has already served on remand.
Judge Robert Adams said: "Trotter admitted Stafford was unaware of the fact he was carrying the weapon.
"Stafford was wearing an Iron Man mask and Trotter had covered his face.
"Stafford acted as lookout and Trotter approached the workers, demanded money and produced the handgun.
"It must have caused terror to them.
"Although you knew it was imitation, they did not.
"They undoubtedly feared death or serious harm had it been fired.
"Anyone who carries imitation firearms puts themselves at risk if armed response were to get involved, they, of course, not being aware it was a toy.
"There is a need to deter people from carrying firearms or imitation firearms."
The court heard both men have shown remorse for what they did.
Glen Gatland, defending, said Trotter had just split from his partner and had mounting personal problems at the time.
Mr Gatland said: "It was one very bad day he was having on July 30 2014.
"He has had a long time to reflect on it while sitting in custody. He is full of remorse."
Peter Schofield, defending said Stafford appears to have got involved to help his co-accused settle a debt.
Mr Schofield added: "He was not aware of the imitation firearm being there."