This page documents a major update currently being worked on.
Therefore, not all official feature names or items are mentioned.
1.18,[1][2] the second release of Caves & Cliffs, is an upcoming major update to Java Edition set to release in late 2021.[3] It was first announced alongside the release of 1.17 snapshot 21w15a when Mojang stated that the Caves & Cliffs update would be split in two.[4] Features from 1.18 were developed alongside 1.17, previewed in official data packs used with a corresponding 1.17 snapshot.
The first fully blind mob (bats, despite relying almost exclusively on echolocation, still have basic eyesight).
When sensing movement, it moves toward the source of the movement.
It follows and attacks players, mobs, and other entities that make vibrations.[note 1]
Warden's not a boss, it's like a natural disaster. It does not attack other Wardens.
When attacked, it path finds toward the player.
Seems to follow the same rules as the sculk sensor when detecting noise.
When it detects a vibration, the growths on its head rattle and light up, similar to the sculk sensor.
If any projectile (e.g. egg, snowball, arrow) lands near the Warden, the mob inspects the location where the projectile landed, due to the projectile creating movement and noise. This feature can be used in order to cause a distraction.
The warden's chest has a glowing core that appears to brighten and dim in tandem with the ambient lighting of the deep dark cave biome.
The core creates a low throbbing sound as it pulses. The sound and animation seem to speed up rapidly when the warden notices a player.
Is about 3.5 blocks tall, making it one of the tallest mobs in the game, exceeding the iron golem and enderman in height and width (the same).[note 2][14]
While in the deep dark cave biome, the ambient lighting occasionally dims temporarily, limiting the player's visibility. This serves as a warning that the warden is nearby.[21]
Planned changes
World generation
More extreme and smooth terrain.
Likely change to the generation of alternate stone types, to make them appear in larger but less numerous deposits.[22]
Possibly seen in a screenshot tweeted by Henrik Kniberg,[23] in which diorite appears to generate in a long and flat horizontal strip, rather than a small unevenly shaped patch.
Ore generation has further rebalancing to add strategy to mining.
This is also largely through the addition of ore veins, which influence surrounding stone.
The new ore distribution compared to the old distribution.
May possibly not be a generated structure, but instead a construction built for the purpose of the Warden showcase.
Trivia
This is the first major update for Java Edition that is split into two updates since Adventure Update in 2011.
Notes
↑The warden does not attack other entities but it does follow the vibrations that they make. (For example it follows a snowball but it breaks upon impact to a block rendering it non-attackable by the Warden.)
↑Height of the Warden is based from the image found on twitter.
References
↑"Minecraft: Caves & Cliffs Update FAQ" – Minecraft Help Center, April 17, 2021. "the first (1.17) this summer, and the second (1.18) around the holiday season"
↑[https://twitter.com/kingbdogz/status/1362097448416649222 "Also, to clarify, the Deep Dark won't take up all of below y 0. Other biomes like Lush Caves and Dripstone Caves will be able to generate there too, it's just that Deep Dark can only be found below y 0.
Grimstone is its natural stone ;)"] – @kingbdogz on X, February 17, 2021