When activated, a message will state "King Slime has awoken!" and the boss will spawn somewhere nearby in the world (keep in mind that he may spawn underground or on Floating Islands). In order to avoid the boss spawning underground, the player may wish to jump as high as they can (preferably using the Rocket Boots or Spectre Boots) before using the item.
- If the player attempts to summon two King Slimes, they will die instantly. The death message (and resulting Tombstone) will say '<player> tried to escape'.
- The Slime Crown is the hardest pre-Hardmode craftable boss summon item to obtain, as a fairly large quantity of Gold Bars is required, along with the fairly rare Ruby, and 99 Gels.
- Players wishing to complete their Ninja Outfits can use Slime Crowns to farm for the necessary pieces, as King Slime will always drop one of the three Ninja items.
- IOS: sometimes the crown will not disappear after use, enabling multiple uses of the crown.
- According to most terraria players, when the slime crown is used, the message, "King slime has awoken!" will appear and the music will start, but will soon stop and king slime would not appear. This might be because king slime spawns far underground and gets too far, then he despawns.
- The item (as well as the boss it summons) could be a reference to the King Slime, a recurrent monster from the video game series Dragon Quest, which wears a crown very similar to the one shown in the item's sprite.
- The crown that is seen in the sprite for Slime Crown is shared from the Gold Crown, but mirrored.
- When the Slime Crown is crafted with a Platinum Crown, the crown still appears golden.
- Crafting recipe reduced from 99 Gel and a Gold/Platinum Crown to 20 Gel and a Gold/Platinum Crown.
- Can also be crafted with a Platinum Crown.
- Added to the game.