Here is a summary list detailing exactly how to find each boss: King Slime: spawns randomly at any time when playing on Normal Mode (not Expert Mode) with a 0–10% chance every day after defeating Eye of Cthulhu. Eye of Cthulhu: Craft a suspicious-looking eye from 20 demon bars at ...
The only way to summon the Eye of Cthulhu is to use the Suspicious Looking Eye. You need six lenses to craft the item, and you must make it at a Demon or Crismon Alter. Alternatively, you can loot the item by looking inside gold and frozen chests in the Cavern and Dungeon or ivy c...