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. Secret seeds use unique world-generating mechanics that differ from normal seeds.

For instance, they may change enemy statistics and behavior, item drops, graphics, theme music and more. 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. Secret world seeds are world seeds which have been discovered as secret easter eggs that generate worlds with strange or unique features.

PC/ Console/ Mobile/ tModLoader-Only Content: This information applies only to the PC, Console, Mobile, and tModLoader versions of Terraria.