Some actors need a whole series to make an impact. These guest stars? They only needed one episode.

From Bryan Cranston’s explosive X-Files role to Tilda Swinton leading a vampire council as herself—this countdown is packed with unforgettable takeovers, surprise cameos, and Emmy-winning appearances. Whether it was comedy, courtroom, or chaos, these guests didn’t just show up—they hijacked the whole show.

We break down 15 legendary TV guest spots that changed the tone, stole the spotlight, and left regular cast members in the background.