Guardians mod/Rock Monarch

The Monarch of the Rock is a Pre-Hardmode boss that is very resistant, has several phases and can only be summoned in caves.

Invocation
The Monarch of the Rock is not self-summoned and requires the player to summon it with the Rock Crown. It can be summoned at any time and the player must be in the cavern layer, but the player does not have to be in this biome to deal damage.

Behavior
The Monarch of the Rock in its first phase behaves the same as the Slime King and every certain amount of damage it receives summons rock slimes. As the phase passes, the appearance of the boss changes, having pointed rocks of different colors depending on its phase.

Phase 2 Move faster and drop fireballs that damage the player.

Phase 3 Begins to launch projectiles that bounce off the walls and damage the player

Phase 4 Projectiles change color and become faster.

Phase 5 In this phase, the boss begins to ram the player without stopping until he dies or kills the player.

Expert Mode
In this mode the boss drops a bag when he dies, has more life (6,500) and does more damage in addition to changing phases faster.