Guide:Skeletron Prime strategies

Skeletron Prime, the Hardmode version of Skeletron, is intended to be the most difficult hardmode boss. His high health, defense, damage, and multiple limbs will take a lot of punishment, and his limbs have the added effect of blocking nonpiercing shots aimed at his head.

Terrain preparation
An ideal arena for Skeletron Prime should consist of several rows of wood platforms. A full stack of 99 for each row should provide ample running distance to avoid his attacks, though it never hurts to have a longer arena. The platforms should be suspended off the ground, to prevent the Prime Cannon's grenades from ever detonating. A solid ceiling should be avoided, since Skeletron Prime will often retreat a fair distance when not using his spinning attack.

Adding some Heart Statues wired to Timers may also prove valuable to keep your health high.

As with all bosses, starting the battle as soon as the sun sets will provide the maximum amount of time to beat Skeletron Prime, which is vital since defeating him can take all night.

Armor
Adamantite armor should be used if the player has not collected the souls necessary for Hallowed armor. Both the ranged and melee bonus helmets are helpful to keep on hand, as the melee bonus can be used to resist Skeletron Prime's initial attacks until his melee capacity is reduced, at which point the ranged bonus will provide extra damage without the defense loss being too much of a concern.

Weapons
The Adamantite Repeater with Cursed Arrows is the optimal weapon for players who have yet to beat any hardmode boss. The Hallowed Repeater and Megashark with Crystal Bullets or Cursed Bullets present a better alternative if either The Twins or The Destroyer have been defeated. Other weapons that work quite well are the Clockwork Assault Rifle (With Cursed or Crystal Bullets) because it has reasonable damage and a good range and Star Cannon and Flamethrower, for their ability to damage multiple parts.

Accessories
Accessories that improve mobility are a must, particularly the Spectre Boots. Angel Wings or Demon Wings will further aid in avoiding his attacks and preventing fall damage. The Obsidian Shield will prevent knockback. The final accessory should help in preventing direct damage; the Philosopher's Stone, Band of Regeneration, or Cross Necklace are all good choices. All accessories should be reforged for damage or defense bonuses, at least +2 for each.

Potions
Bring plenty of Greater Healing Potions, at least ten to be on the safe side. The Regeneration Potion and the Ironskin Potion will help prevent fatal damage, but will often wear out before the battle is over. Two of each will cover the entire night. A Bowl of Soup will provide a further advantage. Also the Gravitation Potion may be useful if you want to free up another accessory slot, although you may want to keep a pair of wings or an Lucky Horseshoe equipped to prevent falling damage. The last type of potions that are very useful are swiftness potions, because they help you evading his limbs, especially if you decide to use a Gravitation Potion instead of Spectre Boots.

The battle
Skeletron Prime is a flying boss that consists of five parts:
 * Prime Saw, a melee arm, with 10000 health.
 * Prime Vice, a melee arm, with 10000 health.
 * Prime Laser, a ranged arm that fires lasers, with 6000 health.
 * Prime Cannon, a ranged arm that fires grenades, with 7000 health.
 * Skeletron Prime, the head, with 30000 health.

Each piece has a specific method of attack, but only killing the head will defeat the boss, meaning the other parts can potentially be ignored. Due their habit of blocking attacks, however, at least one or two should be destroyed to make beating Skeletron Prime easier.

Prime Saw
Prime Saw is Skeletron Prime's most prominent melee attack limb, and the one that will do the most damage of any limb. At regular intervals, it will chase down the player, causing serious collision damage each time it hits. The arm can move as fast as the player can with Spectre Boots, and will accelerate in short bursts so it can catch up. It will eventually pull back to the head, waiting to repeat the cycle.

As it does a lot of damage, this arm should be destroyed first. By using the wooden platforms to change height when it charges, or with great speed, Prime Saw's attacks can be avoided until it is destroyed. Using the melee set bonus will help mitigate damage taken, after which the ranged set can be equipped.

Prime Vice
Prime Vice is Skeletron Prime's secondary melee arm. Though it will occasionally chase the player, it is more common for the arm to simply charge directly at the player, retract, then attack again. This arm is relatively easy to dodge, making it a minimal threat to an agile player.

Prime Laser
Prime Laser will consistently remain above the player, firing one laser every second or so. The lasers aren't as damaging as melee attacks and can be avoided fairly easily, but are harder to dodge if attempting to damage the head. Its low defense and health make destroying it much easier than the other limbs, so it may be worth removing simply to make the head easier to target.

Prime Cannon
Prime Cannon fires grenades at a rate faster than Prime Laser, which also do more damage. However, these grenades only detonate on contact with a solid block. In a wood platform arena, this effectively renders Prime Cannon a nuisance that occasionally blocks attacks. Leaving it intact buys more time to defeat the head.

Skeletron Prime
Skeletron Prime is the head, which must be destroyed to win. Skeletron Prime will try to float above the player at all times (use this opportunity by shooting the head from below), high enough that he may be entirely off-screen at lower resolutions. He'll close in to do his spinning attack, which doubles his attack and defense. Once he finishes spinning, he'll retreat again. If the head is not destroyed by morning, it will be locked in its spinning attack, gain a speed increase, and its attack and defense will increase to nigh-unbeatable levels. In this state, a single hit will kill the player, while the head will only take one or two damage per hit.

When trying to destroy the head, it helps to have destroyed at least two of its limbs first. The remaining two usually won't block too many of your shots. Using the ranged set bonus is recommended, since the extra damage and ammo conservation will make destroying it easier. His attacks are relatively simple to dodge, and though he can cause a lot of damage, getting hit once or twice isn't a very big deal since he doesn't attack too frequently. The wings and Spectre Boots make it almost impossible for it to hit you.

When Skeletron Prime stops attacking and tries to retreat, chase it down using the wings. Though they'll eventually give out, you'll do a fair amount of damage on the way up. The head will come back down fairly quickly. Attack the head constantly and it should be destroyed before morning.