The death of Leonard Nimoy inspired an outpouring of tributes from across the globe — but The Big Bang Theory, which counted Nimoy among its geek icon guest stars, had an unusually close relationship with the actor. A napkin signed by Nimoy led to one of the sitcom's most memorable scenes, and Nimoy later lent his voice to an episode. As a final tribute to Nimoy, creator Chuck Lorre used his customary "vanity card," which appears bearing a new message at the end of each episode, to pay his respects at the end of Thursday's episode: .@BigBang_CBS pays tribute to Leonard Nimoy on tonight's episode #StarTrek #BigBangTheory pic.twitter.com/Gi3FLtD54g — Star Trek (@StarTrek) March 6, 2015