New Mob: Vampire Bats

In Deep Dark or the mysterious cave biome that can only be found in the deepest depth of the world, silence is your only friend but to give it a bit more spice, this mob could make the game even crazier. 

Vampire Bats can be heard flapping their wings to attack you after the Screecher screeches. Vampire Bats are another type of bats, their colors are a bit darker than current Bats but in Maroon, their eyes are bright red, glowing like Spider's eyes but weak. This Vampire Bats cannot be found in any biomes, structures or dimension, they can only spawn once the Screecher screeches. They will chase you for about 8 seconds and will die immediately. I think these ideas could change the game especially in caves and allowing yourself to retreat for a second to prevent any worse situation the mobs could give. Also, I love how the idea plays with sounds, as a contrast of being silent. This is inspired to Boomer from L4D2 and Retch from B4B