Crux is the boss of Red Forest area. It's a creature fused with crystals. Even though this is the reason why he can't move he's ready to defeat any uninvited guests by spitting piercing projectiles or spinning crystals around.
As other bosses Crux has different HP depending on how early a player goes through boss door. The earlier - the less difficult (less HP) boss will be, the later - the more difficult (more HP). The difficulty is represented with the number of skulls in boss health bar.
|Skulls||HP (Health Points)|
Crux boss has different phases/stages and his behaviour depends on which phase boss is currently in. Those phases are: crystal spitting phase, attack/vulnerability phase. Damage can be dealt to Crux only when he's in attack/vulnerability phase. There are 3 different ways a player can take damage while fighting with Crux: damaged by falling crystals, on contact with crystals that are already on the ground, on contact with Crux or it's spinning lines of crystals. More information about each of the phases: