Devon Walker at "SNL50: The Anniversary Special" in February. (John Nacion/Variety via Getty Images)Saturday Night Live cast member Devon Walker announced he is leaving the comedy series after three years, ahead of the popular NBC sketch show's fifty-first season."Me and the show did three years together, and sometimes it was really cool. Sometimes it was toxic as hell," Walker wrote in an Instagram post on Aug. 25. "But we did what we made the most of what it was, even amidst all the dysfunction.