In this add-on Warden Mod, it adds a new blind scary hostile mob called the Warden. It Warden lives in the deepest caves and usually attacks and follows noise or sound, and if you are in a very deep cave and see it, just be sure to stay quiet or run away before it catches you!
Disclaimer: This is an unofficial application for Minecraft Pocket Edition. This application is not associated in any way with Mojang AB.