Minecraft wiki entry for Exploring_an_ancient_city, associated text: The Warden operates on a 60 second-timer. After it spawns in, the timer will start counting down and if the Warden goes 60 seconds without detecting any noise or entities nearby, then it will burrow back into the ground and disappear. After that, it will only return the same way it arrived before; through being summoned by a Sculk Shrieker.