The line comes from Dexter, the Showtime crime drama that aired from 2006 to 2013 and starred Michael C. Hall as the forensic analyst Dexter Morgan. Arthur Mitchell, played by John Lithgow, speaks the greeting when he finally confronts Dexter, closing out one of television's most celebrated villain arcs. Years later the clip took on a second life on TikTok and Reels, where editors use the cold hello for villain introductions, rival meetups and dramatic entrance memes across fandoms.