We've gotten 3 pages in and only 2 cthulhu suggestions? Ok, here goes. First off, we need at least 5 different playable races. Humans, dwarves, goblins, pirates (which are not human) and ponies. Secondly, early-game is too hard. We need to spawn with a ranged and magic weapon, at least early-tier stuff. Spawning with a hookshot would be good, too. The gem hooks are too hard to obtain. Pre-hardmode Hallow is a thing that needs to happen. Weaker versions of wisps, white 'light slimes', and mini-wyverns would be good enemies for it. For the last pre-hardmode suggestion, skeletron should be vastly resized and renamed to the skull and arms of cthulhu.
On to hard mode. The wall of flesh is too hard to summon multiple times. Instead of him killing the guide, have him kill a random NPC of either gender, so you can summon him more times. Secondly, his drops are too random. As we know, randomized drops make games literally impossible to play. He should drop one of each emblem per kill, as well as an item for crafting the weapon of your choice. As balance, he no longer drops the pwnhammer (now made from the earlier crafting item), so you have to fight him at least twice. In hard mode, the mech enemies have been completely removed. Instead, you have to fight the heart, stomach, and mouth of cthulhu for hallowed drops and eventually start... (note that harmode dungeon, jungle, and temple have been removed)
Champion mode! Champion mode is after hard mode. Two new biomes each tear through the world parallel to eachother, one in the underground layer, and one in the cavern layer. The underground layer gets a thin new biome known as The Chaos. It's changed to blocks that will sometimes change the blocks around them into completely random other blocks, including a possibility at more chaos blocks. Chaos elementals spawn here, instead of the underground hallow, and the rod of discord is generated here with 1 per world, in a block similar to the enchanted sword's. The second biome, deeper underground, is the new Lizhard biome. It's a long, snake-like temple with one entrance at the mouth and a marathon of indestructible traps that lead to a new boss at the end; Yig! Leader of the snake people. Defeating him activates..
Mega mode! Mega mode is after champion mode, and features two even newer biomes. Spawning in the sky and themed in angelic and biblical imagery, The Ascension looks decorative at first.. but it turns out that the angel statues DO do something. Angel statues placed throughout the biome will come to life and attack. They become more numerous and aggressive as you approach a central temple, which holds something chained up inside. Free it, and you must fight... the soul of cthulhu! This boss is intangible, and can only be harmed by spiritually-imbued weapons. Spiritual imbuement is a new feature which adds a tag to a weapon to let it hit intangible targets, and is obtained from the other mega mode biome.. The Arcanum! Vertically, on the side of the screen opposite the dungeon, a new tower appears into being from the surface to the top of the sky. This tower has to be entered at a single point and fought up through, much like the New Lizhard. The top of it has a magical altar where souls are sacrificed to spiritually imbue items. One hundred souls of any sort, in any combination, are needed to do this. Defeating the Soul of Cthulhu begins...
Ultimate mode! Ultimate mode is actually simpler than the other modes. Five massive patches are placed randomly through the world of something known as The Eldritch. Your allied NPCs start going crazy and attacking you occasionally (they'll respawn after you kill them, and it's pretty rare). Each of the five patches of Eldritch (a tentacle-themed biome) contains one fifth of the Massa di Requiem per Shuggay. Completely assembling this book allows you to infinitely summon Cthulhu whole. This boss fight teleports the player (and all players on the same team) into a massive, empty space with a strange background. Here, movement is different. The player character is not effected by gravity at all, allowing simple, fast movement in all directions on a 2D plane. Cthulhu is not happy about being forcibly torn out of R'lyeh and onto this even playing field. Cthulhu himself takes up multiple screens, and the parts of him must be defeated individually (head, right arm, left arm, right leg, left leg, torso). Defeating all of them moves Cthulhu to his second phase, in which you fight.. the Concept of Cthulhu. It is a small, floating object that will spawn other, earlier bosses to attack you. Hitting or being hit by them restores CoC's health. CoC isn't damaged by weapons and, instead, slowly takes damage the longer you don't get hit by any of the bosses it's summoned, taking more for each boss trying to attack you. Once it's defeated, it becomes a portal in between your realm and its, an item dropping to let you place your world's portal. This is the end of the game, and it gives you access to this new, enemy-free realm where building and movement are completely unrestricted.
Except... If you have Meowmere. Using Meowmere with a true terra blade makes it true meowmere. Imbuing that specifically with an even number of each type of soul makes it Soul-forged True Meowmere. If this item is discarded and touches either portal, it will spawn Cathulhu. Cathulhu is.. actually not very big. It is a housecat with cthulhu's features. It is, however, very fast and aggressive. Quick reflexes or friends will be necessary to defeat it. Defeating it, however, instead of destroying it, makes it become friendly. It stops moving, and turns into an item, which will let you summon it as an ally to completely wreck whatever enemies dare to glare at you in your home realm.
