Guide:Skeletron Prime strategies

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

Skeletron Prime is the Hardmode version of Skeletron. It is part of the trio of Mechanical bosses, alongside with The Destroyer and The Twins. Its high health, defense, damage, and multiple limbs will take a lot of punishment, and its limbs have the added effect of blocking non-piercing shots aimed at its head.

Spawning Conditions
Skeletron Prime can be spawned by fulfilling any of these conditions: It must then be defeated before all involved players die.
 * After smashing a /, it will have a 10% chance of appearing when night falls, until it is defeated for the first time. This condition is shared with the rest of the trio, so there's a chance that the Destroyer or Twins will spawn instead.
 * Use a.

The Fight
Skeletron Prime is a flying boss that consists of five parts: If you take out its Head, you kill the boss.
 * Prime Saw, a melee arm, with 9000 health.
 * Prime Vice, a melee arm, with 9000 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 28000 health.

Each limb has its own unique attack pattern, listed below. Although killing the limbs is not necessary, they can block the head (especially Prime Saw and Prime Vice), and destroying them can make the fight much easier. It is suggested that you take out the most dangerous limbs at the beginning, as the fight gets significantly easier without them.

Prime Saw
Prime Saw is one of the two melee limbs Skeletron Prime has. It lunges at the player, dealing a lot of damage if its attack connects. However, compared to the other limbs, the Saw is not as aggressive, making it a low priority.

Its predictable pattern, combined with its more passive behavior, makes it a small threat compared to the other limbs despite its high damage.

Prime Vice
Prime Vice is one of the two melee limbs Skeletron Prime has. Compared to the Saw, it does less damage, but it is more aggressive. It lunges at the player, attacking many times before retracting.

Although its pattern can be somewhat predictable, its behavior when Prime is enraged makes it a very dangerous limb capable of dealing a ton of damage if the player is not careful.

Prime Laser
Prime Laser is one of Skeletron Prime's ranged arms. It will consistently remain above the player, firing lasers at a moderate rate. Its shots do a lot of damage and is Prime's strongest limb in Expert mode. The laser starts shooting a lot faster when Prime enters its "enraged" state, making it an even bigger problem.

Its highly damaging, fast and accurate shots arguably make it Prime's most dangerous limb. Because of this, it should be targeted before any of the others.

Prime Cannon
Prime Cannon is the second of Prime's ranged limbs. It shoots bombs that do not destroy tiles, lack contact damage, and ignore platforms. This means that if the player fights in an arena, the Cannon will very rarely do any damage, since the bombs only explode should they land on a solid block.

This, combined with the fact that the bombs are by far Prime's weakest attack, makes the Cannon significantly less threatening than any of the other limbs. The player should focus their firepower on the other arms or Skeletron Prime itself.

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. It will close in to do its spinning attack, which doubles its attack and defense and empowers its other limbs, making them attack more frequently. Once it finishes spinning, it will retreat again.

Like Skeletron, 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 near-unbeatable levels. In this state, a single hit will kill the player, while the head will only take one damage per hit, and two damage per critical hit.

Killing the head is a lot easier once some of its limbs are down, mainly the Vice and the Laser. Focusing only on the head still works should the player wish to end the fight as soon as possible, but usually it is recommended to focus on some of the arms first.

Terrain preparation
As with all bosses, an arena made out of Wooden Platforms greatly increases your mobility, and it will also shut down the Prime Cannon. You will want 10-15 rows of Platforms, each around 50 or so blocks long. The platforms should be suspended off the ground to prevent the Prime Cannon's grenades from detonating too close to you. A solid ceiling should be avoided since Skeletron Prime will often retreat a fair distance when not using his spinning attack.

Armor

 * greatly increase offensive stats, and , provides very high crit chance and its set bonus can hit multiple parts.
 * , is a great choice due to its high stats and the buff.
 * provides lower stats, but it greatly increases natural regeneration with its buff.
 * If you have already defeated a Mechanical boss, becomes a great choice.
 * is the best choice for summoners.

Weapons
For melee users:
 * The, or the  with the  are all very strong choices.
 * The is also an very good choice. Its bouncing properties allow it to hit multiple parts of its body at once.
 * The fires a spinning scythe projectile that will pierce Skeletron Prime and can be acquired from mobs in the Underground Snow biome.
 * Once you have defeated The Destroyer, the s can be very helpful with their long range.
 * Also, if you manage to acquire them, s are a very effective weapon, due to their high damage and speed.

For ranged users:
 * The or, or if another mechanical boss has already been defeated, the  can be easily obtained. Combine them with  or  for high damage.
 * The and  are very powerful guns made even stronger with.
 * If you have defeated The Destroyer, the is a very powerful option due to its insane speed and respectable damage.
 * The is extremely powerful - especially when combined with.
 * The and  are both very strong with  or.
 * It is recommended to use a secondary weapon with ammo, as the debuff will make it significantly more vulnerable to damage.

For Magic users:
 * You can use the which functions similarly to Crystal Bullets and deals high damage.
 * The is just as strong.
 * The is powerful and easy to craft, provided you have some leftover Meteorite Bars from Pre-Hardmode.
 * The deals little damage but inflicts the  debuff, allowing your other weapons to deal even more damage.

For Summoners: 
 * You can use the to summon miniature versions of The Twins.
 * The is very useful for defeating the laser and cannon, as they don't move much and allow the spiders to cling for longer.
 * The is a great choice if you tend to remain in one area the entire battle.

Accessories

 * Accessories that increase your mobility such as the or Wings are a must.
 * An Emblem for your class can increase your damage output significantly.
 * The expert mode exclusive can greatly increase your mobility as well as provide some extra defense.
 * The makes all wings significantly faster, which helps when dodging its attacks.
 * The also expert mode exclusive will reduce damage taken, making it a powerful choice.
 * The increases your base health regeneration and reduces the cooldown on potions, making it a good choice if you have trouble dodging its attacks.
 * The or its upgrades make you immune to knockback, preventing Skeletron Prime from knocking you around.

Potions

 * s are recommended.
 * You can also use if you have beaten Turkor the Ungrateful.
 * For buff potions, the, and  will help out immensely.
 * will complement the defense boost of the Ironskin Potion.
 * Rangers with Bows should bring along an or two.
 * Mages greatly benefit from s and s.
 * Damage increasing potions like the and  are good for everybody.
 * The increases your max health and allows you to take more hits.
 * A will help with extra damage, even non-summoners can benefit from having a summon from something like the.

Tips

 * When using Summon weapons, it is recommended to use the targeting function to focus one arm at a time and reduce the threat Skeletron Prime poses. Simply right-click near one of the weapons to target it and your minions will prioritize that arm.