Skeletron

Skeletron is a boss which can be 'summoned' by talking to the Old Man in front of a Dungeon at night. The Old Man will turn into Skeletron immediately and start attacking you, so be prepared when this happens. This is a difficult boss, do not try to fight him unless you have lots of potions, end-game equipment and/or throwable objects. Rapid attacking weapons work best, for example the Minishark or the Flamarang. A flail like Ball 'O Hurt (or even better, the Blue Moon or Sunfury) will also work if you manage to hit him. The Star Cannon is also extremely effective against him, but you'll need 80-120 stars. Another good strategy is to use Molten Fury with Wooden Arrows or better, because Molten Fury deals 29 base damage + arrow damage (Molten Fury sets Wooden Arrows ablaze, which gives +2 damage, and Wooden Arrows are the easiest ammo the get in the game). If a Fallen Star lands on him, around 1000 damage will be taken. It is important to choose a weapon with high base attack (>30, weapons from the Underground Jungle work well), else you will be beaten by his defense and immense HP.

When you defeat Skeletron, you will gain access to Dungeons, and the Clothier NPC will come to your town. If you try to go into the dungeon by going through the door or digging yourself in without defeating Skeletron first, he will constantly spawn heads that will chase you throughout the dungeon.The heads are full sized skeletron heads that will spin constantly. The longer you stay in the Dungeon, the more that are spawned. During the day these will instantly kill you, dealing 9999 damage. At night they will do the same damage as a skeletron head normally does.

The skulls only spawn when you move in front of the dungeon's back wall even if you placed it.The back wall will only be destroyed above ground. This can be told by a Depth Meter. Destroying the back wall with a hammer will prevent the skull from spawning although being hit by other dungeon mobs will probably knock you over walls you have not destroyed. One way to help this is to use dynamite, which only destroys the back wall. Before summoning Skeletron it is highly recomended that you make a large flat area that you can use as a battling ground during combat.

Attacks
Skeletron will attempt to hit you with his arms by swinging them at you and will sometimes spin his head, put his arms in the air, and chase you with his head. If you take too long to kill him, and the sun comes up the next day, Skeletron will hit you for 9999, killing you instantly.

==Tactics ==

There are a few things to keep in mind when you are about to challenge this boss.

First of all, you should make sure that you have a big, even surface to face him on. Building a long line of dirt above and beyond the dungeon's entrance is a good idea. Just make sure that you can get there fast with Skeletron on your tail.

Secondly (if you have the firepower) you could take out his hands first, as that makes killing the head so much easier. After the hands are dead and the head starts rolling towards you, it's easy to just run slightly ahead of him and hitting him with a long blade, such as Blade of Grass, Fiery Greatsword or Muramasa.

Another great tactic to use is a Phoenix Blaster with about 300 Meteor Shots. Go to the top of the dungeon entrance and spam left click while aiming for his head. This also works with a starcannon if you can get the ammo.

When he is rolling his head at you, you can use The Breaker or the Harpoon to deal massive damage right up close to him. The War Axe of the Night also works.

Lastly, bring a lot of potions and keep the pressure up. You only have until dawn before he despawns.

Focus on his head as it's the life support for the arms. Using hellstone tier weapons ensures an easy win, but still possible with lower tier weapons such as meteor tier or the minishark.

Another way to defeat him is to use Dynamite. Please note this will only work with more than one person.

To do this first you need to make a pit out of the blocks near the entrance.

Now when he does his spinning head attack run to the pit and throw as much Dynamite into the pit and jump in he should follow you and get caught up in the blast doing large amounts of damage if the arms are in range you can kill them with about 6 sticks. After you die and respawn your partner can do the same.

It also helps if you build a house with a bed in and set your spawn point there.

Respawn
Skeletron is currently the only boss that can only be summoned once per world. If you kill him you may enter the dungeon without the danger of skulls being summoned.

If you fail or Skeletron accidently goes too far off screen then you'll have to wait until another day to talk to the Old Man. There have been people who report that the Old Man does not reappear if you fail to kill Skeletron (Most likely a bug) although there are some reports of him reappearing after a new npc moves into your house (unconfirmed). Skulls still attack inside the dungeon however. It is also possible to kill the Old Man with a meteor. It's also possible for the Skeletron to respawn at night.

When the Old Man does not respawn, you can go into the dungeon at night and spawn 1 head, then quickly move upstairs again and kill the head. This will also count as a skeletron kill and the dungeon will be safe. The instant (9000+ damage) kill from the heads only occure at daytime.

Also, a good strategy if you play on a multiplayer server is to build a miniature house with a bed inside it near the dungeon. That way, you can respawn into the fight when you die. Just remember to set your spawn to that bed. It is possible for Skeletron to spawn past the dungeon. When this happens, only his head will appear. The is mostly the case in corrupt caverns. This may be a possible bug. A solution has recently been found that allows you to unlock the dungeon.

If you manage to lure one of the floating heads out of the dungeon (Preferably during night time, so you don't die in a single hit) and kill it, the dungeon will unlock, and the instakill skulls will stop following you.

It is also possible to avoid fighting Skeletron by using a Magic Mirror to go to your spawn, if it is far away from the Dungeon.

Bugs

 * An interesting graphical bug appears when you fail to kill skeletron but survive (if he flies too far offscreen), but see the old man spawn, When you kill skeletron, He will drop multiple headgibs, each dropping it's own items. Twotrons.jpg
 * Another bug is when you defeat both of skeletron's hands and his head will kill you in an instant before you have a chance to attack it.
 * During a blood moon it is possible for four skeletron heads to appear.

Trivia

 * In the Alpha version, the monster had 4000 health instead of 6000 and 3000 in an earlier Alpha.
 * This boss is considered the hardest boss to beat currently, due to his health, but also the most valuable since he guards the dungeon, possibly the best pre-set area in the game, right above the Underground Jungle.

Crashing bugs
Sometimes when you kill the monster, your screen will freeze.