Some on social media joked that the mystery object was one of the orbs from popular anime series Dragon Ball, while others claimed it was a ‘Godzilla egg’.
An X-ray later determined the object was hollow and there was no danger of explosion, with the restrictions lifted at around 4pm, according to Fuji News Network.
The object, which has a protrusion that would allow it to be hooked onto something, closely resembles a mooring buoy, Vice News noted.
But the strange sighting sparked a brief flurry of TV attention and frenzied social media speculation, coming in the wake of the US shooting down a Chinese spy balloon followed by multiple unidentified objects.
Japanese police say they will ask local officials responsible for coastal management to collect the ball.
