BRIGADIER LETHBRIDGE-STEWART: You know, just once I’d like to meet an alien menace that wasn’t immune to bullets.

Terrance Dicks (1935-2019) English screenwriter, author [pseud. Robin Bland]

Doctor Who (1963), 12×01 “Robot,” Part 4 (1975-01-18)
    (Source)

(Source (Video); dialogue confirmed)