I ran over a dead deer and now my car is making.

You need to actually get down on the ground and look. When does the noise occur? With the engine running or does the car have to be moving? What area of the car got hit? Do you see anything hanging down? Did you even try to locate where the noise is coming from? What kind of noise?

An exhaust pipe may have pulled apart, or it could have cracked. The fan might be hitting the radiator. Something could be rubbing on a tire. I could throw out guesses all day and never be right.

It sounds like you may have hit the radiator cooling fan which is now making noise and needs to be bent back into position.