The victim, Munesh Kumar, yesterday was playing pranks with a mechanic Krishan Murari (25) at the latter's shop in a drunken state, they said.
Goaded by the pranks, Murari inserted an air pump pipe, used for filling tubes, in Munesh's rectum and switched on the compressor, Assistant Sub Inspector Kalyan Singh said, adding the victim fainted on the spot as air filled up inside his stomach.
He was immediately rushed to New Medical college hospital where he died during the treatment, Singh said.
The body was handed over to the victim's family after postmortem last afternoon, Singh said, adding investigation is underway in the matter.