King Slime

The King Slime is a mini-boss added in the 1.0.4 patch. As the King Slime takes damage, it slowly spawns additional slimes and also becomes smaller until defeated.

Spawning
Inspection of source code has led to the following conclusions about King Slime spawning behavior.
 * The King Slime spawns only in areas a third of the map away from the spawn point. An easy way to determine if you are far enough from the spawn point is to check for the presence of bunnies, who only spawn within a third of the map from the spawn point. If you can see bunnies, you aren't far enough from the spawn. By "within a third of the map", that means only each outer sixth of the map is viable for the King Slime to spawn.
 * The King Slime has a 1:300 chance to spawn, meaning a Water Candle can actually speed up the process of encountering the King Slime dramatically. Standing stationary with a Water Candle has a roughly 50% chance of spawning the King Slime per day.
 * New in the 1.0.5 patch you can use Battle Potion Battle Potion.png to increase spawn rate for 7 minutes.
 * The King Slime spawns anywhere a regular slime can spawn, meaning that it will not spawn above ground at night but can spawn underground at any time (assuming there is enough space).

Strategy
The King Slime behaves exactly like a normal slime (it uses the Slime AI), except that it spawns other slimes after being hurt by the player. Due to its predictable nature, it is easy for a new player to defeat the mini-boss with even lower tier weapons. The only thing a new player should worry about is dodging the King Slime as it jumps about, as he deals a relatively large amount of damage per hit. To finish the mini-boss quickly, projectiles such as Shurikens or Bows and Arrows are recommended.

Digging a pit two blocks wide is an excellent tactic for fighting the King Slime, which is too large to fit in such a small pit. Placing wooden platforms on top of the pit has the added benefit of keeping the smaller slimes out.

Drops

 * 1 Piece of Ninja Gear: 100% (1:1 chance)


 * Ninja Hood: 33.33% (1:3 chance)
 * Ninja Shirt: 33.33% (1:3 chance)
 * Ninja Pants: 33.33% (1:3 chance)

Trivia

 * If you look closely enough, you can see that there is a ninja inside the King Slime. This would explain why you get ninja clothes when you defeat it. This is not viewable in the data-mined sprite in the table above. (Evidence)


 * In Ninja Gaiden, one of the first bosses is a giant slimy monster that devours you. Armor that resembles Ryu's is the one that King Slime drops, so it might be a reference to that boss.