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 five /  three 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.

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 the Princess sells rare items such as the Slime Staff and Discount Card.

While generating

 * The loading screen for this seed is completely normal.

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

The Constant


The Constant is a new secret world seed added in 1.4.3 which is a crossover with Klei Entertainment's .
 * Seeds (case-insensitive):

This seed 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.

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

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.
 * Due to the way Drunk and Celebrationmk10 seeds are implemented, the list is not exhaustive and any number of 0 can be added before the number seed. Also many other unintended seeds have the same result, like (case sensitive):
 * "now aunt brush", "Joke Disappear Horizon" and "disapprove stiff solution" produce a drunk world.
 * "Thirst of dress", "engineer governor reproduction" and "inform Representative yorai" produce a celebration world.
 * 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