It’s not a bird, believe it or not. This isn’t an aircraft. And it’s not an extraterrestrial. (It’s never an extraterrestrial, whether from Krypton or elsewhere.)

Even a full day after its unexpected appe arance, the origin of a weird, balloon-like UFO that emerged in the sky over Sendai, Japan, about 7 a.m. local time yesterday (June 17) remains a mystery. According to press accounts, the item seemed to be a huge white unmanned balloon with two crossed propellers. According to AFP, the UFO hovered in the sky for many hours, mostly immobile, before floating over the Pacific Ocean.

While a weather balloon may appear to be the most apparent answer (they are commonly available for purchase), a representative from the Japan Meteorological Agency’s Sendai bureau informed AFP that “it is not ours.” According to AFP, Japan’s Chief Cabinet Secretary Yoshihide Suga denied any knowledge of the balloon’s origin at his daily news briefing later that day.

Suga also attempted to dispel concerns that the balloony UFO was a nefarious tool of a foreign government. Earlier on Wednesday, social media discussion over the item was rife, with speculations circulating that the UFO was spreading North Korean propaganda or perhaps the new coronavirus.

The evidence for either of these explanations resembles a large, fat goose egg, much like the balloon itself. Grab a tinfoil hat and check out these weird aerial footage just released by the US government for a genuinely perplexing UFO enigma.