The men walked into the service station in the Taufkirchen area carrying weapons, wearing dark clothes and with their faces hidden by hats and scarves. Two customers and the employee were already inside.
The plan was to threaten the attendant with their firearms and fill their bags with money from the checkout desk after he gave in without resistance and retreat to safety.
In practice, things didn't quite work out that way.
Once they reached the checkout desk, they put the plan into action, brandishing their weapons, demanding money and placing a sack on the counter.
However, the 46-year-old employee believed the men were joking, burst out laughing and refused to give them any money.
Unable or unwilling to make good on their threats of violence, the pair switched immediately to Plan B, abandoning the attempted robbery and fleeing for parts unknown.
“The police definitely advise against saying 'This is a joke, I'm not giving you anything'," police said in a statement.
"Rather give them the money and be happy that nothing bad has happened to you."
Police are calling for witnesses to contact them as the men are still on the run.