BATS OF DOL GULDUR (THE LORD OF THE RINGS)
The Lord of the Rings
The Bats of Dol Guldur were large bats that lived in Dol Guldur.
The Hobbit film trilogy
In the The Hobbit: An Unexpected Journey, the Necromancer sent the bats after Radagast who was searching for the dark magic. In the end Radagast manages to get away on his sled pulled by rabbits.
In the The Hobbit: The Battle of the Five Armies, the bats swarmed in Gundabad, and rallied alongside the orc army led by Bolg. In the battle, they aided the orcs in fighting the dwarves, elves, and men. One was later shot down by Legolas, who managed to hitch a ride on it, and the rest were chased off or killed by the Great Eagles.