This is Mercury, passing in from of the Sun, seen by the NASA/ESA Solar Orbiter.

A huge solar prominence extending out from the Sun's surface can be seen behind Mercury.

It looks like Mercury is in Hades, but it's actually 56.8 million km in front of the Sun. pic.twitter.com/bwSLKuyOKU

— Paul Byrne (@ThePlanetaryGuy) February 20, 2023