Three friends in their early twenties were on their way to a cosplay - short for costume play - event on Saturday morning when their appearance shocked fellow passengers, local police reported.
Cosplay is a role-playing activity where people dress up as characters from video games, comic books, movies and other pop culture fandoms.
But the young men perhaps picked the wrong kind of costumes for the moment, dressing in camouflage with munitions vests and carrying airsoft guns (replicas that fire plastic pellets).
Passersby saw one of the men boarding a bus and, frightened by their outfits and weapons, called the police, Munich police reported.
Fifteen police cars were sent out on a search for the bus, sending out a message to all bus drivers, according to Munich's Abendzeitung. On hearing the call, the bus driver carrying the three friends reported their presence in his vehicle to police.
Twenty officers then pulled over the bus and climbed on board, only to find that the weapons the trio were carrying in their bag were the harmless airsoft guns.
They also had two pocket knives with them, which were confiscated along with the guns.
Police said the three were released after being charged for violating weapons regulations by carrying the knives.
"The whole ordeal is absurd," one of the friends, Patrik M., told the Abendzeitung. "You can't dress up like in Carnival anymore."
Patrik also told Bild that he had dressed in this costume dozens of times before for other cosplay events and had never caused alarm, speculating that concerns about Isis in the wake of the Paris attacks have made people more fearful.
On the Monday following the attacks in Paris on November 13th, police were called to investigate eight different reports of suspicious bags found in Berlin, though no bombs were found.
A threat against the Germany-Netherlands friendly in Hanover just days after the terrorist attacks didn't end in an attack, but nonetheless left tensions running high within the country. The president of the German Football Association called for a ban on fireworks at games so as not to cause alarm after the threat.
A survey last week showed that a majority of the German public fears an increased likelihood of attack now that Germany has joined military action against Isis in Syria.