Sculk Shrieker

A sculk shrieker is a redstone block found in the deep dark biome that can summon wardens.

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.

Usage
Sculk shriekers can "shriek" after getting enabled, which can happen by stepping on it, activating a nearby sculk sensor, or activating a redstone signal. This gives all players within 40 blocks the darkness effect for 12 seconds. Shriekers have a 10 second cooldown per player. Sculk sensors only seem to pass on the warning to shriekers if the sound comes from a player action.

If a sculk shrieker is activated, it creates a "warning" level to alert the Warden. A warden spawns when the warning level reaches level 3. If no shriekers are activated, the warning level decreases every 10 minutes.

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

Trivia

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