Scan a QR Code at Pigglestone Bank and get the "Jet Bell" item. He will appear at the top of the School Roof during the day.
In M02, Jibanyan had somehow time-traveled 20 years into the future alongside Robonyan F and Shogunyan, and followed a now grown Amy. When Amy was trying to push a trolley filled to the brim with heavy boxes, Jibanyan became Jetnyan thanks to his far future counterpart giving him a airplane hat to help out his former owner in the task of pushing the heavy trolley, though Jetnyan had accidentally put too much power into the boosters, sending the trolley careening down the aisles at insane speeds. Eventually, Jetnyan was reverted back to Jibanyan when the trolley went airborne and subsequently crashed, the hat having come off during impact.