That's Jupiter's butthole.

NASA's Juno spacecraft spotted this dark, eerie hole at the center of a cloud vortex in Jupiter's atmosphere. The dark spot, located in a Jovian jet stream, is surrounded by bright high-altitude clouds that appear brighter as they swirl in the sunlight. Juno captured this image on May 29 when the spacecraft was about 9,200 miles (14,800 kilometers) above Jupiter's cloud tops. — Hanneke Weitering