Impostor
The Axe
I have a theory that the Moon-Lord is always aware of the player. Once you get enough health, He summons blood moons to slow down the player to stop them from getting out of control.
After defeating one of the Mech-Bosses that the cultists forced the mechanic to build, He gets angry and causes solar eclipses to directly impede your efforts.
After defeating one of the Mech-Bosses that the cultists forced the mechanic to build, He gets angry and causes solar eclipses to directly impede your efforts.