Warden

A warden is a mob summoned by sculk shriekers. They are completely blind, and thus rely only on vibrations and sense of smell to identify the player and other mobs. Nonetheless, they are extremely powerful and one of the most dangerous mobs in the game.

Appearance
A warden's chest has a glowing core that appears to brighten and dim in tandem with the Darkness effect. The core creates a low throbbing or "heartbeat" sound as it pulses. The sound and animation speed up rapidly as the warden gets more suspicious of or closer to attacking a player or mob.

Spawning
If a sculk shrieker is enabled too many times, a warden will spawn by digging out of the ground. If a warden hasn't been noticed or gotten angry at anything for 60 seconds it will dig back underground and despawn.

Behavior
Wardens are completely blind, if a vibration is made near them, they will go to the place from which the vibration came from. They are also able to smell players that are too close to them.

Gameplay

 * Status effects
 * Darkness might also be triggered by wardens given how the duration of the effect extended past the one imposed by the sculk shrieker in the Minecraft Live 2021 showcase, and as suggested by a tweet from kingbdogz.

Trivia
The warden isn't needed to receive the advancement, Monsters Hunted.
 * Previous names considered for the warden were the "stalker" and the "hollowed".
 * The stalker iteration was tall, asymmetrical and had a glowing core. It occurred in totems throughout the Deep Dark. The stalker would stand completely still to trick players into taking its core and aggravating it, and could transform into a one block high form to prevent players from digging away. That iteration, specifically its appearance and transformation mechanic, felt too clanky and was more goofy than scary, which is why it was scrapped.
 * The hollowed was based off of tropophobia and had white flesh with holes in it. That iteration was deemed too gory by the developers and had to be toned down.
 * In the sixth episode of “The Secrets of Minecraft” it was jokingly revealed that the warden’s personal name is William, similar to how the ender dragon, the wither, and player characters all have personal joke names. The word was also jokingly broken down into the words: war and den.
 * Kingbdogz stated in a tweet that the souls in the warden’s chest is incredibly important to its lore.

Concept artwork
Some concept art in this gallery was originally made for the Caves & Cliffs update.