Video: Frightening and scary and the stuff of nightmares is what it looks like when millions of bats flee their bat caves at the same damn time. This footage is from the Bracken Cave in San Antonio, Texas and it's totally startling because it starts off so very peaceful and ends in frantic chaos. There are bats everywhere! Millions of Mexican free-tailed bats live in the cave and come out for nightly hunts like clockwork. Eek.