A pilot of one of the F-15K fighter jets made a request to the Master Control and Report Center (MCRC) to further investigate the object.
Because the Korean Air Force weren't able to detect the identity of the suspicious object, they scrambled out two F-15K fighter jets. It didn't help matters that China had sent 10 aircraft into Korean airspace just a few days prior due to the THAAD issue.
Upon arriving at the scene, the pilots of the fighter jets realized it was a false alarm; it was only a giant balloon of popular Japanese animation character Doraemon.
The balloon was reported to measure in at 1.3 meters (4.2 feet) by 2.2 meters (7.2 feet).
Upon clearing the situation, an air force official commented, "There have been reports of giant balloon sightings such as this one, and even lanterns due to uncontrollable wind speeds."
Too bad it wasn't a Pokemon balloon... because you know, gotta catch 'em all.