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Skeletron Prime
Skeletron Prime.pngOld-gen console version and 3DS version
Map Icon Skeletron Prime.png
Map Icon
Classic mode icon.png Classic
Expert mode icon.png Expert
Master mode icon.png 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 toConfusedPoisonedPenetrated
Skeletron Prime Trophy.png"The air is getting colder around you..."Skeletron Prime Trophy.png
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.

Arms[]

Prime Cannon
Prime Cannon.pngOld-gen console version and 3DS version
Classic mode icon.png Classic
Expert mode icon.png Expert
Master mode icon.png 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 Saw.pngOld-gen console version and 3DS version
Classic mode icon.png Classic
Expert mode icon.png Expert
Master mode icon.png 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 Vice.pngOld-gen console version and 3DS version
Classic mode icon.png Classic
Expert mode icon.png Expert
Master mode icon.png 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 Laser.pngOld-gen console version and 3DS version
Classic mode icon.png Classic
Expert mode icon.png Expert
Master mode icon.png 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]

Notes[]

This content is transcluded from Mechanical bosses § Notes.

  • 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.
  • With the 10*1/10 (10%) chance of spawning naturally at dusk, the resulting chance for each mechanical boss is initially 3.33*1/30 (3.33%). Once one of them has been defeated, the remaining two have a resulting 5*1/20 (5%) chance of spawning naturally, and after defeating the second one, the last one has the full chance of 10*1/10 (10%).
  • It is possible to summon a mechanical boss pre-Hardmode if the summoning item is brought in from another world. However, if the Wall of Flesh has not been defeated, Plantera's Bulbs will not start spawning.

The Bombs fired by the Prime Cannon will only detonate if they hit solid blocks. They will pass through platforms and Planter Boxes without detonating. On the Desktop version Desktop version, Console version Console version, and Mobile version Mobile version, the Bombs do explode upon contact with platforms and on the Desktop version Desktop version, they also do detonate when hitting Planter Boxes.

Achievements[]

Achievement Buckets of Bolts.png
Buckets of Bolts • Defeat the three nocturnal mechanical menaces: the Twins, the Destroyer, and Skeletron Prime.
Defeat all three Mechanical Bosses.
Achievement Mecha Mayhem.png
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.
Achievement Bona Fide.png
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.
  • Skeletron Prime's attacks can be easily evaded if equipped with high level wings and moving in a wide U pattern, when at the peak of height from your wings use the Shield of Cthulhu or any other dashing Accessories to dodge over and around Skeletron Prime.
    • Most effective in Classic to Expert Mode.
    • Great for summoners or players with low defense .
    • Running away on asphalt fast enough ,with Hermes boots or their upgrades, and any other speed boosts you can get, can cause Skeletron prime's arms to despawn, but his head won't. Use this to your advantage to cheese it if you are having a bad time

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.
  • 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.
  • 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 Desktop version Desktop 1.4.1.2 source code, method AI() in Terraria.NPC.cs (under aiStyle == 32) There may be inaccuracies, as the current Desktop version Desktop version is 1.4.2.3.
  2. Information taken from the Desktop version Desktop 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 Desktop version Desktop version is 1.4.2.3.
  3. Information taken from the Desktop version Desktop 1.4.1.2 source code, method AI() in Terraria.NPC.cs (under aiStyle == 36) There may be inaccuracies, as the current Desktop version Desktop version is 1.4.2.3.
  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 Desktop version Desktop 1.4.1.2 source code, method AI() in Terraria.NPC.cs (under aiStyle == 32). There may be inaccuracies, as the current Desktop version Desktop version is 1.4.2.3.
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