Skeletron Prime

"You feel the air getting colder around you..."

Skeletron Prime is a Hardmode Mechanical Boss which is essentially a harder version of Skeletron. It is summoned with the Mechanical Skull at night. Players have until dawn to defeat it. Skeletron Prime can also randomly spawn at dusk in Hardmode if it has not yet been defeated, in this case signaling its approach via the status message, "The air is getting colder around you..." or "You feel the air getting colder around you...".

The boss music is Boss 1, making this the only Mechanical Boss to share boss music with its Pre-Hardmode variant.

Attacks
Skeletron Prime has four limbs which are all immune to the Poisoned and On Fire! debuffs:


 * Prime Cannon fires bombs that do not destroy blocks, usually up into the air rather than directly at the player. It usually stays above the player.
 * Prime Laser shoots red Death Lasers similar to those of Retinazer and The Destroyer, and is always pointed at a player. It usually stays horizontal to the player
 * Skeletron Prime's Prime Saw and Prime Vice both act similarly to the The Twins when they are charging, but the Prime Laser acts similarly to Retinazer or the Wall of Flesh while shooting laser beams.
 * Prime Saw usually remains under the player, then swipes upwards or downwards.
 * Prime Vice will swipe around wildly, making occasional lunges at the player. It usually remains diagonal to the player.

Skeletron Prime will occasionally enter into a "Rage Mode," in which its attacks become more aggressive:


 * Skeletron Prime's Head will grow spikes and start spinning towards the player slowly. Damage and defense is doubled.
 * Prime Cannon will aim at the player directly and fire rapidly.
 * Prime Laser will fire more frequently.
 * Prime Saw will begin homing directly towards the player's location.
 * Prime Vice becomes more aggressive and frequently lunges towards the player.

Prime itself is much more mobile than its predecessor, and will regularly move off-screen, which can make it difficult to hit reliably with ranged weapons.

Like Skeletron, if it is not beaten by dawn it begins to continually headspin, dealing enough damage to kill most players in a single hit and having 9999 defense, acting like a Dungeon Guardian.

Trivia

 * Skeletron Prime will open and shut its mouth for the entire battle. This, however, has no effect in battle.

Tips

 * Standing on platforms far from blocks can mostly nullify the effects of the Prime Cannon, as its projectiles only detonate on blocks, while passing through platforms harmlessly.
 * Skeletron Prime can be the most profitable boss in the game, as the Souls of Fright can be crafted into Naughty Present to summon the Frost Moon, netting large amounts of money per 5 souls, as well as Hallowed Bars at the same time to make a Pumpkin Moon Medallion to start the Pumpkin moon.
 * A tall arena may be more advantageous because it allows the player to flee upwards. This can be useful when Skeletron Prime performs its spin attack, allowing the player to get rid of any arms giving them trouble.
 * Try killing off its four arms. That way Skeletron Prime's head will not have anything blocking it, which will make the fight a lot easier. Although, this gives you less time to defeat Skeletron Prime's head, it is usually worth it.
 * If you have obtained Wings, then when Skeletron Prime's headspin occurs, you can move away quicker and will allow you to get more hits off on it.
 * Alternatively, make a skybridge like the one recommended when fighting The Twins, and run back and forth, shooting from a safe distance. This is a little difficult, but may be easier to do in some circumstances, in comparison to building a vertical arena.
 * Using Frost armor is recommended due to Prime not being resistant to the Frostburn debuff.