Cranius

Cranius is an Insane Mode boss which is essentially a harder version of Skeletron Prime. It is summoned by breaking the Chaos Spire in the Chaos at night. Players have until dawn to defeat it. Cranius can also spawn at dusk with a 1/10 chance if Psychosis/Brothers Jaw have been defeated, Cranius has yet to be defeated in the current world, and at least one player has at least 600 health and 100 defense. This spawn is signaled by the chat message ''"You hear the sounds of clashing steel from far away..." ''

The boss music is Cranius Theme.

Attacks
Cranius has eight limbs, each of which are immune to all Phase 1 and Pre-hardmode debuffs.
 * Skull Saber will hover directly to the left of the player, occasionally swiping the blade around wildly, attempting to deal damage to the player. This arm has a 50% chance to apply the Cursed debuff for five seconds, making it quite dangerous.
 * Skull Whip acts like the Solar Eruption, swinging back and forth whenever the player gets with its range. It inflicts the Electrified debuff on contact and deals high damage, making it a high priority to kill.
 * Skull Cannon acts exactly like Skeletron Prime's Prime Cannon, except it does much higher damage and fires out three bombs instead of one. This arm poses very little threat.
 * Skull Jackhammer chases the player closely, rapidly inflicting high damage and the Bleeding debuff on contact. This arm can rapidly kill unprepared players battling Cranius, and is such the number one priority to destroy.
 * Skull Saw constantly swings back and forth rapidly, dealing over two hundred damage on hit but held back by its innacurate attacks. High priority to kill.
 * Skull Beam fires out three lasers at high speeds, aiming at the player. The damage on the lasers is low, but the player must constantly dodge the blasts if they don't want to be killed, making it a nuisance one would want to destroy quickly.

Occasionally, Cranius will enter a rage mode where its begins to charge directly at the player to do melee damage and its arms adapt much more aggresive attacks.
 * Cranius Legs pose little threat, firing bombs downwards every few seconds, but destroying them greatly slows the movement of the head, thus usually making it desirable to destroy them.
 * Skull Saber will lock on to the players location and swing at them rapidly.
 * Skull Whip will now target the player directly instead of swinging only when the player moves into its attack area.
 * Skull Cannon will fire red Cranium Bombs that will stick to any tiles, including platforms, and have massive, tile-destroying explosions.
 * Skull Jackhammer will double its damage.
 * Skull Saw triples its damage.
 * Skull Beam will fire far more damaging purple lasers.
 * Cranius Legs will also fire red bombs, and at a much more rapid rate.

Drops
Cranius Mask (14.29)

Cranius Trophy (10%)

Super Healing Potion 5-15

Megametal 30-60

Souls of Height 20-30

Mechanical Broadaxe (1/3)

Electro-Flail (1/3)

Mechanical Jackhammer (1/3)

Cranius Treasure Bag (100%, E. Mode only)

Steelbuster (100%, inside loot bag)

Achievement
Hardheaded "Defeat Cranius, the mechanical monster behind the horrid Chaos, for the first time.