The Warden is a hostile mob that was introduced with Minecraft 1.19. It isn’t a boss, but more like a mini-boss, due to the amount of health it has. They’re one of Minecrafts most interesting creatures, as they rely on vibrations to locate enemies.
Wardens can be disabled from spawning completely by using the command /gamerule doWardenSpawning false in-game.
How to Spawn a Warden
Wardens are able to naturally spawn within the Deep Dark Biome. You’ll have better luck finding the Deep Dark by checking under Biomes like Mountain Peaks or Plateaus. When you’ve found the Deep Dark, you’ll notice that it’s covered in different Sculk blocks.

If you can’t find the Deep Dark, one option is to use a command. If you have cheats enabled, then enter the following command in Minecraft, then click the shown coordinates to teleport to that location: /locate biome minecraft:deep_dark
The Deep Dark is mostly made up of Sculk. Occasionally, you can find Sculk Sensors and Shriekers. When a Sculk Sensor detects vibrations, such as those of a player walking around, they’ll emit a signal to nearby Shriekers, which will emit particles as shown below when they become activated.

They’ll also Shriek if a player is standing directly on top of them. To spawn a Warden, you need to cause a Shrieker to activate at least 4 times in a short period, then it will call upon the Warden, which will climb out of the ground.

One way to prevent the spawning of the Warden is to sneak while in the Deep Dark. This will prevent any Sensors or Shriekers from becoming activated. When one of these blocks are triggered, they’ll have a 10 second cooldown before the warning level is increased.
Spawn Using Commands
The Warden is only able to be spawned in the Deep Dark, from naturally generated Sculk Shriekers. If a Sculk Shrieker is mined, even with Silk Touch, it won’t be able to summon a Warden.
If you can’t find the Deep Dark, or want to summon a Warden elsewhere, the only way to do so is using a command. In Minecraft, enter the following command to summon a Warden: /summon minecraft:warden