Secret world seeds

Secret world seeds are world seeds which have been discovered as secret that generate worlds with strange or unique features. Unlike regular world seeds, which affect only the usual world structure, secret seeds can produce worlds with characteristics that would not be attainable through normal world generation, i.e., they can affect the game's mechanics while playing in that world. For instance, they may change enemy statistics and behavior, item drops, graphics, theme music and more.

Secret seeds use unique world-generating mechanics that differ from normal seeds. Using a secret seed overrides the normal use of seeds as a source of randomness and two worlds created via the same secret seed will not necessarily be identical.

There are currently eight different secret seeds.

Drunk world



 * Seeds:

This seed references May 16, 2020, which is Terraria's 9th birthday and the release date of 1.4.0.1. It invokes a highly extraordinary world generation referred to in the source code as drunkWorldGen. It has therefore come to be referred to by the Terraria community as drunk world.

In this seed, both Evil biomes will generate, as well as both variants of any ore that comes in two varieties. The Guide is replaced by the Party Girl as the starting NPC, and the Dungeon entrance is now generated under a Living Tree painted brown.

While generating

 * Generation descriptions and tips become random numbers that change every tick (except when "").
 * The background shows a Glowing Mushroom biome, with clouds that resemble Redigit's head. The moon moves backwards and resembles a smiley face (see Trivia). Once the world finishes generating, it is possible to go back to the main menu with these effects still visible.
 * The outline of the progress bar rapidly flashes between Corruption and Crimson.
 * The Console Title music plays, instead of the normal Title Screen theme.
 * The Terraria logo spins out and disappears along with the version number.
 * The time of day is always night, and it never turns day.

World icons
The world icon of a drunk world shows a tree infected with both world evils.

Not the bees



 * Seeds (case-insensitive):

This seed generates a world dominated by bee-themed biomes and bee-related items and structures.

Most of the world is replaced with the Jungle biome, with Hive and Honey Blocks found in abundance, and Larvae spawn throughout the world. The starting NPC is the Merchant instead of the Guide. He will sell the Furnace as per usual in the Jungle.

While generating

 * While generating, all generation descriptions say "".

World icons
The world icon of Not the Bees world is a Rich Mahogany surrounded by Bees.

For the worthy



 * Seed (case-insensitive): for the worthy

This special world's features aim to drastically increase the difficulty of the game.

All enemies' contact damage, health and coin drop rates are increased, in addition to the world difficulty multiplier, by their standard amount in a normal world. After that, the damage is increased by another. Damage from ranged attacks is typically left unchanged. Bunnies (even placed) are replaced with Explosive Bunnies, and all Demons are replaced with Voodoo Demons. The Demolitionist replaces the Guide upon entering the world for the first time.

There are also many other changes to world generations and game mechanics. For instance, some water pools throughout the world are replaced with lava. Pots and trees may drop lit Bombs that shortly explode, instead of their usual items. Skyware Chests are replaced with locked Gold Chests but they still have their respective loot.

Bosses also receive changes to size and/or AI that make battles much more difficult.

While generating

 * The world generation screen messages are spelled backwards.

World icons
The world icon of a "For the worthy" world is a Yellow Willow tree.

Celebrationmk10



 * Seeds (case-insensitive):

This seed celebrates Terraria's tenth birthday, May 16, 2021.

The player's spawn point is on the beach of one Ocean. Andrew the Guide, Whitney the Steampunker, Yorai the Princess, a Party Girl, and an Angora Town Bunny will also spawn there and a Party immediately starts. A majority of the world is painted in bright colors.

Items in chests always have a "best" modifier such as Menacing or Legendary.

Two unique enemies can be encountered in this seed:
 * The Jungle Mimic can be found in the Hardmode Jungle.
 * Golden Slimes can rarely spawn.

The chance of obtaining rare items such as the Rod of Discord and developer items is substantially increased, the Traveling Merchant always sells 2 extra items, and the Princess sells rare items such as the Slime Staff and Discount Card.

While generating

 * The text on the loading screen is pink.

World icons
The world icon of a Celebration world is a Pink Sakura tree with a bowknot.

The Constant


This seed is part of the crossover with Klei Entertainment's .
 * Seeds (case-insensitive):

It introduces hunger and darkness mechanics that make the early game especially challenging. Marble biomes with statues and Spider Caves will generate on the surface, and Cacti will damage the player.

The entire game uses a dark shader that gives the game a gloomier look. Items exclusive to the Don't Starve crossover content are more likely to drop.

While generating

 * The game adds "" as one of its messages.
 * A constant shader which significantly darkens the screen will be applied.

World icons
The world icon of a Constant world is an from Don't Starve.

No traps

 * Seeds (case-insensitive):

This seed includes extra traps despite its name.

While generating
The message "Placing Traps" is replaced with the message "Not Placing Traps".

World icons
The world icon of a No traps world is the same as the regular icon with Wire coming from the base of the tree.

Remix Seed



 * Seeds (case-insensitive):

This seed flips the usual order of player progression through biomes by having the player spawn in the Underworld.

The Underworld now contains Ash Trees, and lava does not spawn in the central part of the Underworld. Lava slimes do not drop lava upon death. In addition, Mimics now spawn in pre-Hardmode, but drop Surface loot.

A number of Hardmode weapons, including the Ice Bow, Keybrand, and Unholy Trident can be found pre-Hardmode, however their attack power is reduced to be more in line with pre-Hardmode weapons.

There is a Glowing Mushroom biome immediately above the player's spawn.

Fallen Stars can be found by breaking pots, and do not disappear during the day. They are also sometimes carried by slimes.

The Guide is replaced by the Tax Collector.

The Surface is entirely covered by either The Corruption or The Crimson, depending on which world type was chosen during generation. Stone on the outer edges of the map are also replaced.

The entire Surface has low gravity, no visible sun or moon, and the skybox is a star field with shooting stars.

Crossing above the top border of the world now results in the players death, resulting in unique death messages.

The Dungeon, Jungle Temple, Living Trees, and any Pyramids are all painted either red or purple, depending on the world evil.

The Jungle Temple generates on the Surface.

Living trees appear dead with barren branches and few leaves.

Cloud Blocks and Sunplate Blocks on Floating Islands are replaced with Lesion Blocks or Flesh Blocks. Floating Islands also contain a water fountain of the world evil.

Surface enemies will spawn in the center of the Underworld during a Blood Moon.

Surface weather events like Rain and Blizzards can occur underground.

Invasions can also occur underground.

While generating

 * The Terraria logo rotates and flips upside down.
 * The background becomes a field of stars with shooting stars streaking through it.

World icons
The world icon of a Don't dig up world is an Ash Tree.

Everything / Zenith Seed
This seed is a combination of no traps, not the bees, drunk, celebration mk10, don't starve, remix and for the worthy secret seeds.
 * Seeds (case-insensitive):

As with the Remix seed, the player spawns in the Underworld on a flat plain with ash grass and Ash trees, and a Glowing Mushroom biome immediately overhead, however the Glowing Mushroom biome here will be painted in rainbow colors.

Andrew the Tax Collector, Whitney the Steampunker, Yorai the Princess, a Party Girl, and Slimestar the Diva Town Slime will also spawn there and a Party immediately starts. When the Party ends at the beginning of the first night, all of them will instantly die.

Heart and Star pickups are randomly replaced with their counterparts from the Christmas and Halloween events.

Defeating Wall of Flesh does not generate the Hallow. Additionally, the Steampunker does not sell Clentaminator or any solutions.

Instead of naturally occurring spawn of the Twins (?), a new boss may spawn named Mechdusa, prompting the message "Mechdusa has awoken". Mechdusa is essentially the amalgamation of all three mechanical bosses, shaped into a single creature, resembling a gorgon from Greek mythology, with the Destroyer as it's body and Skeletron Prime serving as its head with the Twins being sprung out of its eye sockets. Despite being spawned as such, all three of them still possess their own independent health pool. AI of the Mechdusa is also a result of combination of all three AI models, with the priority being Skeletron Prime > The Twins > The Destroyer (?).

Though the Zenith world does use the hunger and darkness damage systems from The Constant, it does not use the shader.

Worlds with this seed will use an upscaled world difficulty, so Journey > Classic, Classic > Expert, Expert > Master, and Master > Legendary. The Legendary difficulty is a secret difficulty only available on this seed, though what it specifically does is yet to be confirmed.

While Generating

 * All text will be backwards except for the text "Not Placing Traps". The same text appears when generating a No Traps seed.
 * The logo will be flipped upside down and the background will be replaced with a field of stars like it is in the Remix seed.
 * The cursor will be changed to a face made out of two stars and a moon as it is in the Drunk seed.
 * Falling stars can be bounced off the cursor which makes the same sound as a meowmere.

Trivia

 * The smiley-faced moon seen during the generation of a drunk world is a reference to an astronomy hoax that was said to happen the same day Journey's End released on PC.
 * Unlike the other secret seeds, the drunk world and Celebrationmk10 seeds are interpreted as numbers, so any number of 0s can be added in the front (e.g.  for the drunk world). In addition, there are numerous unintended strings that generate these two secret seeds (due to the use of the ), such as:
 * Drunk world (case-sensitive):
 * Celebrationmk10 (case-sensitive):
 * If a modified world were to have 2 or more active secret seeds at the same time, the icon for it would follow this priority: Drunk world > For the worthy > Not the bees > Celebrationmk10 > The Constant.