What is this search bar on my desktop?

I dont know what this search bar, but it appears randomly and sometimes at the bottom left corner of the desktop. it types everything I write (when it's there). For example, when I want to go to facebook from chrome, I type "face" and press enter, I automatically go to the "face"time app on my mac. Its driving me! Why is it there? How do I get rid of it? Help!