The Warden is an upcoming hostile mob in the 1.17 - Caves and Cliffs update.
The Warden will be the first blind mob to be added to Minecraft. Instead of following the player normally, it uses the sculk-like sensors on its head to detect vibrations.
A good defense to use in order to avoid fighting the Warden is to sneak or throw projectiles such as snowballs or arrows to distract it, which was shown during the Minecraft Live 2020 event. It was shown in the reveal that the Warden will be attracted to projectiles that produce a sound. However, fighting the Warden is not recommended, as it does a lot of damage.