What is this?

So I was driving along the highway and a cat ran in front
of me. I had no time to stop and unfortunately hit the cat. I
pulled over to check and see if everything was okay
underneath my car and saw this (see uploaded picture). I
had someone take the piece off so it wouldn't drag while I
drove. I'm not a car person can someone tell me what this
piece is and if it's okay to drive without it. Thank you in
advance.