The Twins

The Twins are a Hard Mode boss introduced in the 1.1 patch, and look very similar to the Eye of Cthulhu, although they not only are faster and much more resistant, but also possess a wide arsenal of attacks which can prove deadly to the unexperienced player.

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The boss fight can only be initiated by using a Mechanical Eye. Although the Mechanical Eye requires Souls of Light, that are only available in a world where the Wall of Flesh has been defeated, The Twins can technically be summoned in any world, regalordless of whether or not Hard Mode has been unlocked in it. The Twins will only remain as long as it is Night, and will flee the battle at dawn.

Upon death, The Twins are guaranteed to drop 20-30 Souls of Sight and 5-15 Greater Healing Potions. Defeating them is the only way of obtaining Souls of Sight.

The Twins initially consist of two eyes connected together, one named Spazmatism and the other Retinazer. They maintain separate health bars, and are not considered defeated until both are killed (the first killed Twin will not leave any loot). Each of these two eyes has a unique AI routine, as well as a second form that it will transform into when it is below half health.

Retinazer (First Form)
 * In its first form, Retinazer will shoot lasers at the player and occasionally close in slowly to make a series of melee attacks. The lasers do not pass through blocks.

Spazmatism (First Form)
 * Spazmatism, in its first form, will shoot cursed flame projectiles at the player and occasionally make a serie of lunges at the player. The projectiles do not pass through blocks.

Retinazer (Second Form)
 * In this form, Retinazer gains significantly more defense and a much more frightening laser attack. It will always float above or to the left of the player and use its ranged attack. Occasionally it will begin to shoot its laser in rapid-fire bursts. It will never attempt to use its melee attack, preferring instead to maintain a constant distance between itself and the player. Note that in this form, Retinazer will not even attempt to shoot at the player if it does not have a clear line of sight, and its lasers do not pass through blocks.

Spazmatism (Second Form)
 * Spazmatism's second form is the most threatening part of The Twins, as it possesses the most defense, the most damaging attacks and the greatest mobility. It will alternate between rapidly charging at the player to use its insanely powerful melee attack, and slowly giving chase while using its medium-range cursed flame breath attack. In this form, Spazmatism will not use the cursed flame attack if it does not have a clear line of sight.

General Tips
This section contains a list of quick tips that players can incorporate into their strategies.

Strategic Tips

 * You should try to avoid fighting both Twins in their second form at the same time. Try to kill them off one at a time. Since Spazmatism is statistically the deadliest of the two, you may wish to begin by eliminating him.
 * Do not try to fight at high altitudes where the Wyvern spawns. Fighting the Wyvern and The Twins at the same time is not recommended.
 * Play the game on a high resolution in fullscreen so that you can see The Twins from further away. This can help you to predict their movement patterns more easily.
 * Because Retinazer (Second Form) never attempts to use a melee attack and will not fire at you unless it has a clear line of sight, once Spazmatism is beaten you can build a small "box" with an opening and shoot at Retinazer with impunity.

Offensive Tips

 * Do not use melee or short ranged weapons against The Twins. They generally deal less damage than ranged alternatives, while simultaneously making yourself an easier target for The Twins' powerful melee attacks.Trying to melee Spazmatism in its second form, due to its long-range breath attack and surprising speed, is basically suicide.
 * In order to deal damage quickly with as little risk to yourself as possible, use powerful long ranged weapons. The best weapons for this fight are the Crystal Storm, Megashark and the Star Cannon. Note that Crystal Storm should always be used with the Mana Flower.
 * Make good use of all damage-boosting items available. This includes items such as the Sorcerer Emblem, Magic Power Potion, Bowl of Soup and Crystal Ball for casters. For ranged-weapon users, consider items such as the Ranger Emblem, Archery Potion and Crystal Bullets. Armor set bonuses can also increase your damage output, as can Reforging.
 * When the target you're shooting at is moving, always "lead" it by aiming slightly in front of its intended path. This will ensure that a greater percentage of your projectiles hit.

Defensive Tips

 * Always come to the fight with the best defensive equipment possible! Full Adamantite Armor is recommended for this battle. You should strongly consider the possibility of using the melee helm just for more defense, even though it won't boost the damage output of your ranged weapon.
 * The Obsidian Shield and Cross Necklace are both awesome accessories that can greatly boost your defensive capabilities.
 * It is recommended to Reforge some or all of your accessories to obtain defense boosts.
 * Don't forget about the wonders of the Ironskin Potion.

Movement Tips

 * Wide open areas allow for more freedom of movement. Enclosed areas will hinder your movement options, but provide better cover against the duo's ranged attack.The ideal field to fight should be a tunnel about 300 blocks long and 6-8 blocks wide, in order to block enemy projectiles when they're above or below and back away and shoot them when they attempt to melee.
 * Effective dodging requires both vertical and horizontal movement. A large number of items can allow for increased mobility, such as the Gravitation Potion, Angel Wings, Rocket Boots, Wood Platforms, Magic Mirror and Grappling Hook, just to name a few.
 * Practice dodging ranged attacks by fighting against Corruptors or Gastropods. This may help you to improve your dodging skills before taking on The Twins.
 * You can instantly engage the speed boost of the Spectre Boots or Hermes Boots by using the grapple hook trick, which is extremely useful for running.

Healing Tips

 * Items such as the Regeneration Potion and Band of Regeneration are not particularly helpful in this battle, although they are a welcome help when trying to dodge a barrage while the potion cooldown is still in effect.
 * Always make use of any Heart Statues in your possession. They are one of the best healing methods in the game. Remember that each heart statue is worth 2 hearts every 8 seconds!
 * The Philosopher's Stone reduces healing potion cooldown by 15 seconds, which makes healing potions far more effective in boss battles.
 * If you set your spawn point to be inside the Nurse's room, you have a Magic Mirror, and you're fighting not too far away from your house, you can quickly teleport home in an emergency and immediately restore yourself to full health. Afterwards, remember to get away from your house immediately so that the boss doesn't kill your NPCs.
 * If you're fighting in an area of your world that the Hallow and Corruption have not spread to, weaker enemies will spawn there. Killing them is a free source of hearts--this is most effective during a blood moon.

Strategies
The following is a list of strategies that players can employ to defeat The Twins. Remember that making good use of certain tips above can greatly increase the effectiveness and success rate of these strategies.

1) Sky

 * This strategy hinges on the usage of the Gravitation Potion, possibly in conjunction with the Featherfall Potion to constantly fly around in the air, dodging the vast majority of attacks that The Twins unleash. It is reccommended to equip an accessory for increased air mobility, like the Rocket Boots or Wings. It is also absolutely necessary to have an accessory that negates knockback, such as the Obsidian Shield or the Cobalt Shield.


 * When attacking, keep in mind that the bosses will constantly home on you, so try to anticipate their movements and not to reverse gravity too suddenly, or they might move out of the way of your projectiles.


 * Video demonstrations of this strategy can be found on youtube: (e.g. http://www.youtube.com/watch?v=LZRVvqpZbRU. Note: do not try to fight the Wyvern like in this video. It is wiser to stay away from the upper atmosphere so that it never spawns.) Hero also has a video that beautifully demonstrates this strategy over on the Skeletron Prime page.

2) Skybridge

 * Simply build some Skybridges and run on them, using a Grappling Hook or other mobility-enhancing item to quickly switch between them to move out of the way of a melee charge or barrage.


 * This strategy can work wonders by building a Nurse's house at the start of the skybridge and setting the spawn point there. When low on health the player can teleport back, have the nurse heal them and resume the fight before the Twins have a chance to harm her. Beware that if the player has walked too far from the spawn point, teleporting will make the bosses despawn.

3) Statue Corridor

 * For this strategy, employ plenty of Heart Statues. Using a wide wire grid to connect at least a row of them to pressure plates will cause them to drop plenty of hearts, allowing you to rapidly skip through them and regain lots of health. You can place a row of statues pretty much anywhere to take a small break from the fight in any moment.

4) Sand Coffin

 * This strategy takes advantage of the short invincibility the player is granted after taking any damage. It requires some Sand (or Silt, Pearlsand, Ebonsand, Spikes, etc.), a Cross Necklace, some healing potions, a good defense rating and a Cobalt Shield or Obsidian Shield to negate knockback. The Philosopher's Stone is also recommended.


 * To execute the strategy, simply stand in an open space from where you'll have a 360° line of sight, then have some sand fall on you. This can be made easier by using the Ice Rod and making a floating platform to remove later. The sand will continuously deal 1 damage, thus negating most damage from other sources. Keep in mind that some attacks might still hit you, but that can be remedied by regularly consuming potions.

Multiplayer Strategy
With the help of one or more friends, fighting the bosses becomes much simpler. With one player luring Retinazer away and taking cover to avoid its attacks, others can concentrate their fire on Spazmatism and kill it quickly, and successively go back to Retinazer and defeat it. Be careful, as if either the player luring Retinazer or all of the ones fighting Spazmatism are defeated, one of the bosses might despawn, making it impossible to defeat both and thus gain the spoils.