In a bizarre subway episode Wednesday night, an unsuspecting straphanger suddenly found himself in possession of a handgun.

The 33-year-old man was standing on the L train platform at 14th Street at 8:30 p.m. when he felt a heavy weight drop into his backpack, law enforcement sources told The Post.

Turning around, he saw two strange men walking behind him. He checked inside his backpack and found a black semi-automatic.

For some unknown reason, the two men then decided they wanted the gun back — along with the backpack they’d dropped it in, sources said.

There was a brief struggle over the bag. But its owner prevailed, breaking free of his two attackers and running — backpack, gun and all — into the NYPD’s nearby Transit District 4 station.

Cops are now seeking the two indecisive gun donors — and the gun itself will be tested to see if it is linked to any crimes or individuals, sources said.