Aaron Bailey is Michelle's recurring classmate. He is the typical class bully, who tends to be annoying and rude (especially towards the members in the Tanner household) at times. He pinches Michelle in the Season 3 episode "Bye, Bye Birdie" when they are in preschool, and Jesse tells Michelle to fight back. When the teacher punishes them, Jesse takes Michelle home. While that behavior is discontinued, his obnoxious ways do continue throughout the series.
Danny even remarks in a Season 7 episode that they are watching Aaron for several days "until his regular babysitter stops twitching". Aaron's last appearance is in Season 8's"Dateless in San Francisco".