Boss Monsters

A Boss Monster is normally an NPC found rarely in Terraria that is much harder to kill than other monsters. It generally has much stronger attacks than a normal enemy, more defense, and considerably higher HP. In addition most boss monsters have their own AI, allowing them set movements to go by.

Many bosses can be summoned by an item like the Suspicious Looking Eye or Worm Food. These are the most widely known of the bosses throughout Terraria:
 * King Slime
 * Eye of Cthulhu
 * Eater Of Worlds
 * Skeletron
 * Wall of Flesh
 * Wyvern Mini-boss
 * The Twins
 * The Destroyer
 * Skeletron Prime

Eye of Cthulhu

 * Main article: Eye of Cthulhu.

The Eye of Cthulhu (commonly referred to as The Eye) is usually the first boss players will encounter, this is due to the fact that The Eye is the easiest pre-hardmode boss. The Eye comes in two forms. The first form has and deals 15 attack damage, while the second form has  and has 23 attack damage. The Eye of Cthulhu can be summoned by using a Suspicious Looking Eye (which can either be found in random chests or can be crafted from 6 Lenses at a Demon Altar) at night. The Eye can also spawn itself if certain criteria are met. While playing, the player may get the message, "You feel an evil presence watching you...", which means that the Eye will awaken soon. After a few minutes the message "The Eye of Cthulhu has awoken!" will appear and the boss will promptly start to attack the player.



Eater of Worlds

 * Main article: Eater of Worlds.

Eater of Worlds is a worm type boss monster. He can be summoned in the corruption by smashing three shadow orbs and he can also be summoned with worm food, which can be crafted at a demon altar. Eater of Worlds is made out of 53 parts in three forms; head body and tail. To beat this boss you need to slay all his parts. If you destroy the head, the first body segment will automatically take its place. The same works with the tail. But if you destroy a body segment, he is going to split into two worms. But overall if you avoid the heads massive attack which consists of 40, you should beat the boss no problem.

Skeletron

 * Main article: Skeletron.

Skeletron is a boss which can only be fought once per world. He is summoned by talking to the Old Man infront of the dungeon at night and choosing the option "Curse". It is advised to be prepared because after that he'll turn into Skeletron and attack you. His hands each have and his head has. His hands do 30 damage if they touch you and his head will do a spin attack that does 35 damage. Be quick to defeat this boss and summon him at the very beginning of night because once dawn comes Skeletron will hit you for 9999 damage. The only way to fight Skeletron again is by creating a new world, or by using a map editor.

The Twins

 * Main article: The Twins.

The Twins are the hardmode counterpart to the Eye of Cthulhu.

The Twins are bosses summoned with the item "Mechanical Eye", which is crafted at a Mythril Anvil after summoning and killing the Wall of Flesh. In order to make a Mythril Anvil, one must kill the Wall of Flesh, use the Pwnhammer and break Demon Alters and "Bless your world" with Cobalt, Mythril, and Adamantite.

The Twins are usually considered the easiest Hardmode boss. It it usually the first for players who recently killed the WoF.

The Destroyer

 * Main article: The Destroyer .

The Destroyer is a worm type boss monster. He is the Hardmode counterpart of the Eater of Worlds. However, unlike the Eater of Worlds, it does not split into parts.

The Destroyer is summoned with the item "Mechanical Worm ",which is crafted at a Mythril Anvil after summoning and defeating the Wall of Flesh.

The Destroyer drops 15-30 Souls of Might and 5-15 Greater Healing Potions. Souls of Might are required to make many Hardmode weapons and tools. Getting the souls can sometimes be a problem, as if the Destroyer is defeated while mostly underground the Souls of Might may be dropped on top of blocks.

Skeletron Prime

 * Main article: Skeletron Prime .

Skeletron Prime is the Hardmode counterpart of Skeletron. Similar to The Destroyer, he is also made of metal.

Skeletron Prime is summoned with the item "Mechanical Skull", which is crafted at a Mythril Anvil after summoning and defeating the Wall of Flesh.

Skeletron Prime drops 20-30 Souls of Fright and 5-15 Greater Healing Potions. Souls of Fright required to make many Hardmode weapons and tools.

King Slime
Main article: King Slime 

King Slime, as said by it's name, is a slime. It is blue in colour and quite large, roughly 10 blocks wide and 5 blocks high. It will decrease in size and spawn blue slimes when it takes damage. It appears to have a Ninja trapped inside it.

King Slime is summoned with the item Slime Crown, crafted with a Gold Crown and 99 gel at a Demon Altar. There has been a bug associated with King Slime, sometimes causing the boss to not spawn/appear. This may be due to the fact that he spawned inside a cave and cannot get out.

King Slime drops a LOT of Gel when he dies, a piece of the Ninja Set and some lesser healing potions. The blue slimes spawned drop Gel as well.