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Skeletron Prime
Skeletron PrimeOld-gen console version and Nintendo 3DS version
Map Icon Skeletron Prime
Map Icon
Classic mode icon Classic
Expert mode icon Expert
Master mode icon Master
Statistics
Type
Environment
AI TypeSkeletron Prime Head AI
Damage47/79/119
94158238 (while spinning) [1]
Max Life28000/42000/53550
Defense24
48 (while spinning) [1]
KB Resist100%
Immune toPoisonedConfusedPenetratedTentacle SpikeBlood Butchered
Skeletron Prime Trophy"The air is getting colder around you..."Skeletron Prime Trophy
Not to be confused with Skeletron, the pre-Hardmode boss.

Skeletron Prime is a Hardmode mechanical boss which is essentially a more difficult version of Skeletron. It consists of a head and four limbs, but, similarly to Skeletron, only the head needs to be defeated to defeat the boss.

Skeletron Prime can be summoned manually using a Mechanical Skull at night (7:30 PM to 4:30 AM). It also has a 10*1/10 (10%) chance to spawn naturally at dusk once a Demon or Crimson Altar has been destroyed, as long as it has not yet been defeated at least once in the current world. If spawning this way, its arrival is announced by the status message "The air is getting colder around you...".

If Skeletron Prime is not defeated by dawn, it will behave much like a Dungeon Guardian: It will cease using its limbs and instead charge at the player at extremely high speeds, dealing usually lethal damage upon contact.

While Skeletron Prime is alive, the music Boss 1 will play. When Otherworldly music is enabled, the track Boss 2 (Otherworldly) will play instead.

Quick Answers

What does 'the air is getting colder around you' mean regarding Skeletron Prime? toggle section
In the game Terraria, the phrase 'the air is getting colder around you' is a significant indicator that the boss Skeletron Prime is about to spawn. This phrase appears as a status message to alert players of the impending challenge. Skeletron Prime, a Hardmode mechanical boss, can also be manually summoned using a Mechanical Skull, but this phrase typically signifies its natural appearance in the game.
Provided by: Fandom
How can you summon Skeletron Prime using a Mechanical Skull? toggle section
Skeletron Prime, the weaponized mechanical variation of Skeletron, can be summoned using a Mechanical Skull. This boss-summoning item is used to call upon Skeletron Prime, a Hardmode version of Skeletron. However, it's important to note that the Mechanical Skull can only be used at night. So, if you're planning to summon Skeletron Prime, make sure to wait until the sun goes down and the air is getting colder around you!
Provided by: Fandom
What is the chance of Skeletron Prime spawning naturally at dusk? toggle section
Skeletron Prime has a 10% chance to spawn naturally at dusk in the world of Terraria. This event is usually announced with the status message 'The air is getting colder around you...'. Remember, this only happens if Skeletron Prime has not yet been defeated at least once in the current world.
Provided by: Fandom
What are the differences between Skeletron and Skeletron Prime? toggle section
Skeletron Prime is essentially a more difficult version of Skeletron, a boss character in Terraria. Unlike Skeletron, Skeletron Prime is a Hardmode mechanical boss with a head and four limbs. The limbs are unique, consisting of a vice, a laser gun, a saw, and a cannon that shoots bombs. While both bosses require only the head to be defeated, Skeletron Prime's head spins, increasing its Defense, unlike Skeletron whose Defense drops to zero when spinning. Additionally, Skeletron Prime is more mobile, often flying off-screen, making targeting more challenging. It's also worth noting that Skeletron Prime can be summoned as many times as you want in a world by crafting and using a Mechanical Skull, but only at night. Remember, when you're about to face this boss, 'the air is getting colder around you'.
Provided by: Fandom
What happens when you defeat only the head of Skeletron Prime? toggle section
When you defeat only the head of Skeletron Prime, you've essentially won the battle! Despite Skeletron Prime having four limbs – a vice, laser gun, saw, and cannon – only the head needs to be defeated for a successful victory. This is a unique feature of this boss in Terraria, making the 'air getting colder around you' a thrilling moment for players as they summon Skeletron Prime.
Provided by: Fandom

Arms[]

Prime Cannon
Prime CannonOld-gen console version and Nintendo 3DS version
Classic mode icon Classic
Expert mode icon Expert
Master mode icon Master
Statistics
Type
Boss Part
Environment
AI TypePrime Cannon AI
Damage30/51/76 (melee)
80160240 (Bomb) [2]
Max Life7000/10500/13387
Defense23
KB Resist100%
Immune toPoisonedConfused
Prime Saw
Prime SawOld-gen console version and Nintendo 3DS version
Classic mode icon Classic
Expert mode icon Expert
Master mode icon Master
Statistics
Type
Boss Part
Environment
AI TypePrime Saw AI
Damage56/95/142
Max Life9000/13500/17212
Defense38
KB Resist100%
Immune toPoisonedConfused
Prime Vice
Prime ViceOld-gen console version and Nintendo 3DS version
Classic mode icon Classic
Expert mode icon Expert
Master mode icon Master
Statistics
Type
Boss Part
Environment
AI TypePrime Vice AI
Damage52/88/132
Max Life9000/13500/17212
Defense34
KB Resist100%
Immune toPoisonedConfused
Prime Laser
Prime LaserOld-gen console version and Nintendo 3DS version
Classic mode icon Classic
Expert mode icon Expert
Master mode icon Master
Statistics
Type
Boss Part
Environment
AI TypePrime Laser AI
Damage29/49/73 (melee)
50100150 (Death Laser) [3]
Max Life6000/9000/11475
Defense20
KB Resist100%
Immune toPoisonedConfused

Behavior[]

Skeletron Prime's head constantly endeavors to remain between 31.5 and 12.5 tiles above the player and within 6.25 tiles of either side of the player. It can accelerate infinitely in order to move back into this area. The head does not actively attempt to make contact with the player.[1]

Skeletron Prime's four limbs all have unique attacks:

  • Prime Cannon fires BombBombs every 2.33 seconds that do not destroy tiles[4], usually up into the air rather than directly at the player. It usually stays above the player.
  • Prime Saw usually remains under the player, moving up and down.
  • Prime Vice will swipe around wildly, making occasional lunges at the player. It usually remains diagonal to the player.
  • Prime Laser shoots red Death Lasers every 3.33 seconds, similar to those of Retinazer and The Destroyer, and is always pointed at a player. It usually stays horizontal to the player.

Every 10 seconds, Skeletron Prime will enter a spinning phase for 6.67 seconds, in which its attacks become more aggressive:

  • Skeletron Prime's head will grow spikes and start moving towards the player at 10 mph, exactly like how its pre-Hardmode counterpart Skeletron does. Damage and defense are doubled to 94 / 158 / 238 damage and 48 defense.[1] In Expert Mode, the base spinning speed is 31 mph and is increased the further the player is away, up to a maximum of 76 mph at a distance of 37.5 tiles.
  • Prime Cannon will aim at the player directly and decrease its cooldown between firing to 0.67 seconds.
  • Prime Saw will begin homing directly towards the player's location.
  • Prime Vice becomes more aggressive and frequently lunges towards the player.
  • Prime Laser will fire lasers every 1.33 seconds.
  • Skeletron Prime lets out a roar every time it enters the spinning phase.

Upon dawn (4:30 AM), Skeletron Prime will enrage and permanently behave like a faster Dungeon Guardian, increasing its velocity[5] and usually killing the player instantly if touched: its damage increases to 1000 and its defense raises up to 9999.[1] It will remain in this state until defeated, even if it becomes night again. If defeated, it will drop items normally.

If the player is more than 375 tiles away, Skeletron Prime will start moving downwards and will quickly despawn.[1]

SkeletronPrimeSpinning

The boss during the spinning phase


Health in Multiplayer[]

  • In Expert and Master modes, the health of bosses depends on the number of players in multiplayer. Please enter the number of players (a whole number between 2 and 256) on your server in the input box below.

    If you don't see the input box and the Calculate button, please check if you have JavaScript enabled in your web browser (instructions for the most popular web browsers). If you're certain that JavaScript is enabled but the button and input box are still not appearing, please contact the administrators on the Terraria Wiki:Admin noticeboard.

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  • Skeletron Prime

    Notes[]

    This content is transcluded from Mechanical bosses § Notes.

    • There is a 10*1/10 (10%) chance for a random mechanical boss the player has not defeated yet to spawn naturally at dusk.
    • When spawning naturally, a mechanical boss spawns exactly 81 seconds after the status message has appeared. Being in a layer lower than the Surface at that moment, or, in singleplayer, exiting the world during that timespan, will prevent the boss from spawning naturally.

    Achievements[]

    Achievement Buckets of Bolts
    Buckets of Bolts • Defeat the three nocturnal mechanical menaces: the Twins, the Destroyer, and Skeletron Prime.
    Defeat all three Mechanical Bosses.
    Category: Slayer Slayer
    Achievement Mecha Mayhem
    Mecha Mayhem • Do battle against the Twins, the Destroyer, and Skeletron Prime simultaneously and emerge victorious.
    Defeat all three Mechanical Bosses simultaneously in a single battle.
    Category: Challenger Challenger
    Achievement Bona Fide
    Bona Fide • “You have defeated Skeletron Prime!”
    Defeat Skeletron Prime for the first time.

    Tips[]

    For more elaborate strategies on defeating Skeletron Prime, including weapon and arena recommendations, see Guide:Skeletron Prime strategies.
    • Standing on platforms / Planter Boxes far from blocks can mostly nullify the effects of the Prime Cannon, as its projectiles only detonate on blocks, while passing through those tiles harmlessly.
    • Unhindered movement is crucial when Skeletron Prime's head starts spinning, as it deals double the regular damage. Wings greatly aid in moving vertically, and flattened terrain or a sky bridge are convenient for horizontal movement.
    • Although it is a little more time-consuming, focusing on the arms first is very rewarding. Once Skeletron Prime's head is no longer shielded by anything, the fight becomes a lot easier. Prioritize damage on the arm which is causing the most damage or disruption, so it can be destroyed and removed from the fight as quick as possible.
    • A good idea is to focus on the Prime Laser first, as it is harder to dodge than the other limbs.
    • Due to Skeletron Prime's overall high defense, inflicting it with Ichor is effective, as it is not immune to it. Note that most Ichor weapons lack in damage compared to other weapons, so they should only be used periodically for inflicting the debuff.
      • In fact, as the head is immune to Cursed Inferno but not Ichor, Crimson world players have a clear advantage over Corruption world players in this sense
    • if fighting with friends, fisting can be a great strategy as you now outnumber his hands, allowing you to easily overpower him.

    Trivia[]

    • Skeletron Prime will open and shut its mouth for the entire duration of the battle, except for when its head is spinning. This is a purely cosmetic effect.
    • It is the only mechanical boss whose name contains the pre-Hardmode boss's name. Furthermore, it is the only mechanical boss to share boss music with its pre-Hardmode variant. Additionally, its name does not begin with the word The, unlike the other two mechanical bosses.
    • Unlike Skeletron, Skeletron Prime's defense doubles when its head is spinning.
    • Although Skeletron Prime's head is immune to Cursed Inferno and Penetrated, its limbs are not.
    • Normally, Skeletron Prime's head has 2000 less HP than Plantera, but in Expert Mode and Master Mode, they both have the same amount.
    • The Bombs fired by the cannon resemble the Dirt Bomb, with different coloring on one half.
    • Skeletron Prime is the only boss with more than two arms.
    • The sprite file for Skeletron Prime's arms is named Arm_Bone_2.
    • Because Skeletron Prime's spawn priority is unusually low, if a circumstance occurs in which several enemies are present at a time while Skeletron Prime is alive, such as setting enemy spawn rates to the maximum in Journey Mode, Skeletron Prime may instantly despawn to make room for new enemies.
    • Official Terraria Lore – According to the official game lore, Skeletron Prime was one of the three mechanical recreations of Cthulhu's missing organs. It is a recreation of part of Cthulhu's skeleton.
    • There is no Dungeon Guardian Prime.

    The BestiaryBestiary entry for Skeletron Prime: "Mechanically reconstructed for reviving Cthulhu, this Skeletron has more arms than ever before, and a variety of fierce weapons."

    See also[]

    History[]

    For changes which affect all the mechanical bosses, see mechanical bosses history.
    • Desktop 1.4.1: Skeletron Prime is now vulnerable to Cursed Inferno.
    • Desktop 1.2.3:
      • Increased health, damage and defense of most parts.
      • Now drops Skeletron Prime Mask.
      • Fixed bug where the player could defeat Skeletron Prime by destroying the Prime Cannon hand and not Skeletron Prime itself.
    • Desktop 1.2:
      • Now has a chance to spawn naturally at dusk with the message: "The air is getting colder around you...".
      • Will now drop 20–40 Souls of Fright, instead of 20–30.
      • Now drops Skeletron Prime Trophy.
      • Reduced health, damage and defense of all parts and head.

    References[]

    1. 1.0 1.1 1.2 1.3 1.4 1.5 Information taken from the PC version PC 1.4.1.2 source code, method AI() in Terraria.NPC.cs (under aiStyle == 32) There may be inaccuracies, as the current PC version PC version is 1.4.4.9.
    2. Information taken from the PC version PC 1.4.0.5 source code, method AI_106() and method Kill() in Terraria.Projectile.cs (under type == 102) There may be inaccuracies, as the current PC version PC version is 1.4.4.9.
    3. Information taken from the PC version PC 1.4.3 source code, method AI() in Terraria.NPC.cs (under aiStyle == 36) There may be inaccuracies, as the current PC version PC version is 1.4.4.9.
    4. In For the worthy, the Bombs do destroy tiles.
    5. Skeletron Prime's velocity is based on its distance to the player, following this formula: \text{velocity}_{\text{mph}} = \frac{9}{11} * \text{distance}_{\text{tiles}} + \frac{1125}{22} It ranges from 51 mph at a distance of zero tiles to 164 mph at a distance of 137.5 tiles, where it is capped. Information taken from the PC version PC 1.4.1.2 source code, method AI() in Terraria.NPC.cs (under aiStyle == 32). There may be inaccuracies, as the current PC version PC version is 1.4.4.9.
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