Sculk Shrieker

A sculk shrieker is a redstone block found in the deep dark biome that summons a warden when alerted too many times.

Natural generation
Sculk shriekers can be found within the deep dark biome.

Breaking
Sculk shriekers can be mined with any tool, but hoes are the quickest. It drops experience when mined without Silk Touch.

Post-generation
A sculk catalyst has a 1% chance of generating a sculk shrieker on top of a sculk block.

Usage
Sculk shriekers can "shriek" after getting enabled, which can happen by a player stepping on it, activating a nearby sculk sensor, or activating a redstone signal. The shrieker shrieks for exactly 90 game ticks (4.5 seconds). After the shrieking ends, all Survival players within 40 blocks are given the Darkness effect for 12 seconds. Sculk sensors only seem to pass on the warning to shriekers if the sound comes from a player action.

Sculk shriekers have a 10 second cooldown per player. This means that if a player triggers one shrieker, then triggers another shrieker within the cooldown period, that shrieker does not activate. The cooldown period includes the 4.5-second shrieking, meaning the shrieker can shriek again 5.5 seconds after the previous shrieking ends.

A sculk shrieker has a spherical range of 16 blocks. When a shrieker is activated via redstone power, if there is a player within 16 blocks, the shrieker starts shrieking; if there is no player within range, the shrieker does not shriek.

Spawning wardens
Each time a sculk shrieker is activated, it adds 1 to a "warning" level to alert the warden. The warning level is specific to each player, not each sculk shrieker, meaning that the same player can activate a different skulk shrieker for each of the three times, and a warden will still spawn on the third activation, despite that that particular shrieker has only been activated once. If a player does not activate any sculk shrieker, the warning level decreases by 1 every 10 minutes.

When a player's warning level reaches level 3, the sculk shrieker attempts to spawn a warden after its shrieking ends. Up to 20 attempts are made to spawn a warden within a 11×13×11 box centered on the shrieker. If there isn't another warden within 48 blocks, and the light level is lower than 11, a warden emerges from the ground.

If the player that triggered the sculk shrieker is outside the shrieker's range when the shrieking ends, or if the shrieker is destroyed before it stops shrieking, the sculk shrieker does not apply the Darkness effect to any player, nor does it spawn a warden. The player's warning level will still increase by 1 regardless.

Trivia

 * The sculk shrieker's design was inspired by the human larynx.