The Skulk Bat

The skulk bat is the natural enemy of the plant. They are 3.5 blocks long from the front nostril to the tail tip and 2 blocks tall with a wingspan of 5 blocks and hunts using smell and will hunt at least once every in-game day. They'll screech if they don’t find food to disorient any other creatures nearby and draw out plants (They are immune to the disorient effect) they spawn in a new structure called the sculk den. They are neutral and hunt in groups and can be bread using plant jaws. The babies will not hunt but will stay in their dens while the adults bring them food. The bat (when harmed) will screech to alert other bats if they need help or keep away any other creatures. The warden will attack the dens and the bats will fight it off ( they have 15 hearts of health).

I really think these creatures would be really cool to see because they would add a lot of life and danger to the deeper areas of the overworld.