King Slime

King Slime is an optional slime boss that does not spawn naturally during world generation. Instead, he is summoned by placing a Crown Summoning Idol on any slime boss rune. Any slime boss arena can be used for the fight, which makes him more flexible to encounter than bosses tied to a specific location.

At full health, King Slime only becomes aggressive toward players within 6 tiles. Once damaged, his detection range expands to 20 tiles. He attacks like the other slime bosses by leaping toward the nearest player, damaging anything at the landing point and leaving a patch of Ground Slime behind. He also breaks any non-indestructible objects in his path, including walls, and will fill pits or liquids with terrain based on the rune used: Dirt, Grass, Beach, or Lava Rock Block. If the player leaves his range or he moves more than 25 tiles from the rune, he returns to it and regenerates 10% of his maximum health every 5 seconds.

King Slime also summons support during the fight. For every 700 health he loses, he creates one Royal Slime. These minions chase and attack nearby players, and they despawn automatically after 60 seconds. When King Slime reaches 30% health, he becomes enraged and moves much faster, making the final phase significantly more dangerous.

His health and damage scale with difficulty:

• Casual: 12,094 health, 72–86 damage
• Standard: 24,188 health, 143–173 damage
• Hard: 36,282 health, 285–347 damage

Because the arena can be any slime boss rune area, a common approach is to use Glurch’s arena for convenience. Clear all Ground Slime before the fight, then enlarge the usable space only slightly, keeping it within 25 tiles of the rune so he does not reset. Since he destroys walls in his path, it is usually better to keep the arena simple and avoid placing important structures where he can smash them. If using the Sticky Stick, many dirt pillars can be placed around the outer edges to help with ricochets, but these are best kept away from the boss’s direct path.

A steady movement pattern works well against his jumps, since it is often possible to avoid most of his attacks by moving continuously. The Royal Slimes are the main pressure point in the fight; if they are ignored, they can accumulate and overwhelm the player. Weapons with wide area damage are especially helpful for clearing them, such as the battle axe or fireball staff, while the Grubzooka can deal with tightly packed groups efficiently. In multiplayer, a focused ranged weapon such as the arcane staff can help concentrate damage on King Slime while teammates handle the adds.

Useful preparation includes armor and consumables that support survivability and mobility. Iron armor is effective for a general-purpose approach, while Caveling armor or Hivebone armor suit physical damage builds. Soaring armor works well for magic builds thanks to its speed bonus, and Chieftain armor is the strongest choice for summoners. An Owlux pet is also useful because it increases movement speed and damage. For food, yellow blister head is valuable for its slime debuff resistance, and options such as dagger fin, pink palace fish, and teal palace fish support summoner, melee, and ranged builds respectively. Healing potions are strongly recommended.

King Slime is not required for progression, so the fight is mainly for enjoyment and for his unique drops, including the King Slime Crown and the Oozy Royal Egg.