Actor Ron Palillo, who played Arnold Horshack on "Welcome Back, Kotter," died of a heart attack on Aug. 14, 2012. He was 63.
Photo: Ron Palillo arrives at the 6th annual TV Land Awards held at Barker Hangar on June 8, 2008, in Santa Monica, Calif.
Ron Palillo, 1949-2012
Credit: Todd Williamson/Getty Images for TV Land