Bats

Bats are one of the most important animals in the world. They help to keep by eating flying insects, transporting and depositing seeds throughout the landscape, and even help to fertilize the ground with their feces, which is known as guano.
They do become a problem if they get into your home. The guano can be hazardous to your health and cause respiratory issues. While they usually avoid contact with humans, if they feel trapped they could potentially bite.