A judge has ordered a 17-year-old to pay a $750 fine and perform 120 hours of community service for contaminating salad dressing with semen and returning it to a suburban Chicago high school’s cafeteria.

DuPage County Judge Terence Sheen also placed Marco Castro on two years probation Wednesday and ordered him to write a letter of apology to Wheaton North High School officials. Castro must complete his community service work for an agency that works with AIDS patients.

Sheen called the prank “beyond stupid.” “If you prove to me you’re worthy of another chance, in two years, then I will give it to you,” Sheen said.