The cast of NCIS pays tribute to David McCallum, who played Dr. Donald "Ducky" Mallard on the show for many years. The actors shared their condolences and memories of working with McCallum on their social media pages. Mark Harmon, who leads the NCIS family, expressed his admiration for McCallum and sent his condolences to his family. Ducky's character was known for his quirks, such as wearing colorful bow ties and talking to dead bodies. Although McCallum had limited screen time in recent years, his legacy on the show will be honored in future seasons.