Nothing.
This question literally comes up hundreds of times each year. It’s not a big deal. If colleges rejected every applicant with a typo, they would not be able to fill their class.
Chill. Read the “clam fart” thread [url=http://talk.collegeconfidential.com/what-my-chances/470497-clam-fart-oh-my-god-what-did-i-do-p1.html]here[/url]. He was accepted.