Cthulhu was a possible boss. Re-Logic was considering its addition at one point, but he was replaced by Moon Lord. While Cthulhu itself never made an appearance in Terraria, a number of enemies and items include direct and indirect references to Cthulhu.
|克蘇魯之眼||One of the first bosses that will be faced by the player.|
– 根據官方遊戲傳說，it is one of the organs ripped out from Cthulhu when he was defeated.
|克蘇魯之腦||The pre-Hardmode boss of The Crimson.|
– 根據官方遊戲傳說，while the Mechanic has almost finished recreating Cthulhu, his complete restoration would require a brain. The brain in question is the Brain of Cthulhu, one of the vital organs ripped off when he was defeated. Also, the lore claims that only "chunks" of the brain was ripped out, meaning that the Brain of Cthulhu is one of the fragments of the actual unseen brain, which can be presumed to be much larger than the Brain of Cthulhu
|骷髏王||The pre-Hardmode boss that guards the entrance to the Dungeon.|
– 根據官方遊戲傳說，Skeletron originally was a part of Cthulhu's skeleton that the Dryads ripped from him.
|機械 Boss||The bosses found in Hardmode.|
– 根據官方遊戲傳說，the Mechanic was forced by the Lunatic Cultist to rebuild a mechanical version of Cthulhu to replace the vital organs that were ripped from him before his disappearance. The three mechanical bosses are the mechanical parts of Cthulhu's organs, with The Destroyer being the spine, The Twins being the eyes, and Skeletron Prime being the skeleton.
|月亮領主||The final boss in the game. It resembles common depictions of Cthulhu.|
|克蘇魯之仆||A minion summoned by the Eye of Cthulhu.|
|克蘇魯真眼||An invincible enemy summoned by Moon Lord.|
|遠古幻影妖||A minion summoned by the Lunatic Cultist. It resembles Cthulhu's head and is also reminiscent of the head of Moon Lord.|
|克蘇魯護盾||An Expert Mode-exclusive item dropped by the Eye of Cthulhu.|
|克蘇魯魚||A quest item for the Angler. It resembles a Demon Eye.|
|克蘇魯之眼||A post-Plantera yoyo dropped by Mothron during a Solar Eclipse, referencing the namesake boss.|
- – 根據官方遊戲傳說，before the events of the game, Cthulhu did exist in the world and almost destroyed it, before an ancient race of Dryads defeated him at the cost of almost their entire race. Cthulhu was not killed, but was crippled when a few organs were ripped from him. After that, he retreats to the Moon and plans for another attack. (Which contributes to proving his relevancy with Moon Lord.)