I just had the biggest scare while mining; So, when caves and cliffs was announced I was TERRIFIED of the skulk, especially the warden; And guess what I heard while mining. I had dug a really long tunnel, I'd mine 5 blocks into each side of the tunnel going toward where I went down.
(I had broken a few pickaxes so I wanted to increase my chances of find diamonds with the rest of them)
and I mined into a wall, skulk sensor detects the sound, and boom. Skulk shrieker goes off. I'm surprised it didn't detect me earlier. I know you have to activate them 3 times to summon a warden, but I still didn't want to be anywhere near that thing. I pressed sneak and probably went way too far for it to detect me again; I know, I'm a baby.