Celestial Skies/The Observer

The Observer is a Pre-Hardmode post-Skeletron boss fought anywhere on the surface at night.

Spawn
The Observer doesn't spawn on its own and requires the player to summon it with the Cosmic Eye while on the surface at night.

Behavior
The Observer hovers around the player with 4/ orbiting star projectiles that will fire explosive mini-stars at the player. After a while, the stars will then be launched at the player for much larger explosions. The Observer will then respawn the large stars and begin the process again.

Trivia

 * The Observer's theme is Oculus, which was composed by the artist SpectralAves.
 * The Observer was the first boss added to Celestial skies.