I love bats, so I thought I would work on this quick little exercise. The idea was to create flying bats as particles in the simplest way possible. I created a bat model with a low amount of polys in the body and a higher count in the wings to account for the flapping. There are two UV sets, one for the simple colors of the bat itself, and then another for top down for the WPO mask. The rest is simple particle animation and material work. Once they are in a mass and flying at speed, little details are completely missed, so there wasn't really a need to be too fussy.
Bat Particles Exercise