Caves are large underground sections of the world filled with unique features. They are so large that they are generated as whole new maps upon entering. Caves have their own artwork, terrain, and maps. Various creatures, plants, and other objects that do not appear elsewhere reside within Caves, but a lot of the same can also be found in the depths.
A Cave can be found underneath a Plugged Sinkhole. Upon mining the plug, an open Sinkhole appears with a rope leading down into a new Cave. Each Sinkhole connects to a different Cave. Each Cave is generated just like a new world. A different loading screen (pictured above) will play while it is created. While within a Cave, time in the world above continues to pass and vice versa. Once a Sinkhole is unplugged, Batilisks (see below) can emerge at Dusk and roam the surface world.
Each Cave begins in a small circle of light with a rope hanging down and a skeleton at the bottom. The worlds within a Cave are affected by the Day-Night Cycle, Cycle of the Moon, and the four Seasons. Caves are always dark depending on the locations. This means that Sanity slowly drains and, in areas of complete darkness, characters are vulnerable to Charlie. Some natural light does leak in from the surface at places, however, and there are other light sources as well. When the map is opened, players will see a new set of icons and terrain specific to the underground (pictured at right).
Giants and Hounds will not spawn in caves. If a player skips a hound wave while spelunking, the wave will occur as soon as the player emerges from the cave. If a player skips the spawning of a giant, that giant might also spawn upon resurfacing (sometimes skipping the warm-up "growling" period). Staying in a cave until the season changes will prevent the previous season's giant from attacking in this manner.
Depths Worm Attacks
In place of Hound and giant attacks, Depths Worms will attack the player at intervals similar to the Hound wave attacks on the surface, and will increase in intensity as the days spent in the world increase. Like Hound attacks in the surface, Depths Worms will automatically target the player unless distracted by another mob.
Earthquakes
While underground, the player may experience Earthquakes. When this happens, the screen shakes and a rumbling sound plays. Rocks, Flint, Nitre, Marble, Gold Nuggets, and sometimes Red and BlueGems will fall from the Cave ceiling. Each of these is preceded by a small shadow and causes damage if it hits the character. Many of the items that fall during an earthquake shatter when they hit the ground, but some will remain intact. Once the earthquake ends, Slurtles and Snurtles leave their homes and roam the Cave in search of minerals to eat.
Stalagmites are a common sight in any cave, and can be mined for Rocks, Gold, and Flint. Similar looking Spilagmites are home to Cave Spiders and Spitters, which can only be destroyed with a Pickaxe. Less common are the Slurtle Mounds, which spawn slow-moving Slurtles and rarely, Snurtles. Additionally stalactites and various rock formations can be found in the dark areas of the caves.
The 'heavenly light' that shines on the sinkhole when the player exits the caves.
Nightmare Fissures can be encountered in the caves, which look like jagged cracks in the ground, with a color that changes based on the Ruins' place in the Nightmare Cycle. Like the Plugged Sinkhole to the Ruins, 2-3 Nightmare Creatures which can detect and attack the player regardless of sanity level will spawn nearby. If the player has experience with combat, and prepares/chooses his ground carefully, these monsters can be farmed for Nightmare fuel, though the constant sanity drain in the caves should ensure hostile encounters with nightmare creatures anyway.
In the Reign of Giants DLC, Rabbits and Moleworms can fall from the ceiling during earthquakes along with other items. They will be in their 'stunned' state as if they were just dropped by a player, but will behave as normal shortly afterwards.
Don't Starve Together
In Don't Starve Together, the Caves received some re-balances. Their generation algorithm has changed to be more like the surface world, having fewer dead-end corridors. Gunpowder no longer starts earthquakes. Light Flowers now only light up when a player approaches them, and they now have a dormant state to prevent players from exploiting their limitless light.
Since the ruins were moved to the same level of the caves, players must now have double caution when venturing through the darkness.
Unlike Don't Starve that has 3 separate Cave worlds, Don't Starve Together only has one Cave world per server, with a single Ancient Guardian.
If a player is inside the caves during Summer, Cave-ins can occur which drop Boulders around the player. These are caused by the Antlion on the surface.
Trivia
Caves were added in the May 21st Underground update.
The Caves used to have giant walls making it hard for the player to see. They were later removed.
When Caves were first released and the player died in one, they would reappear at the Sinkhole at the surface taking no reviving items to get revived. The player could retrieve the lost items, but all the food would turn into rot.
Caves will often generate long stretches of ground that end up leading to nowhere. These can become deadly traps if the player is pursued down one.
According to Maxwell'squotes, he plugged up the cave entrance "a long time ago," and if the player mines it open, he will state that it was a bad idea to do so.
Before the Game Update 165304 of Don't Starve Together, only dedicated servers could support caves, otherwise unplugged sinkholes would have roots blocking path.
On the subject of character unlocking in Don't Starve, Kevin said: "I'm not against having a secret character unlock down in the depths of the cave, but it would probably end up being a more esoteric one, like Wortox or something else non-human".
To create convincing audio for the caves, Klei sent their audio department to the Britannia Mining Museum to record the sounds and impulses of a real life cave.[1]
The caves are the best location for a summer base.
Bugs
When dying in Caves or Ruins, exiting the game right at the death moment will cause the Cave or Ruins world to reset. Upon reloading, the player will spawn in a new Cave or Ruins world and lose all the items along.
This bug can be exploited to make rare non-renewable items such as Green Gems and Thulecite renewable without using the Wooden Thing. This bug works only if the player doesn't have any resurrecting structures active.
After sleeping in a cave, the morning tune and evening tune play at the same time.
If the player starts a fire above the ground and then goes underground, no matter how much time is spent in the cave, the same fire will still be burning upon the player's return.
If one gets killed while going up/down a sinkhole, and they have a Touch Stone activated or a Meat Effigy built at the surface, the world will forever be stuck in the loading screen.
If the player plants seeds in a farm during Winter and then goes down into a cave, the crops will grow.
Sometimes when leaving the caves the Seasons glitch and the player jumps two seasons ahead (Autumn instead of Spring, Winter instead of Summer, etc.). The day count is unaffected.
Occasionally when entering a cave for the first time the generated cave will not be saved after the player exits, causing a new cave world to be generated every time it is entered. When entering a sinkhole, players should be prepared for both scenarios of entering an existing cave and entering a new cave. Making structures in a cave or leaving rare items in a cave is not advised until after it can be confirmed that the generated cave is being saved.
