The main prank that we play with props is for people’s birthdays. The special effects people will put a little explosive in the cake so it blows up in their face - that’s always fun to play on a guest star, or one of the trainees or someone who’s new.

Bell describes a light, behind-the-scenes tradition of practical joking on a film/TV set, emphasizing how prop and special-effects departments can turn everyday celebratory objects into controlled gags. The quote highlights the collaborative, playful culture that can develop during long productions, where birthdays become opportunities for bonding and for gently initiating newcomers (guest stars, trainees) into the show’s social world. It also underscores the technical artistry of effects crews: even a “prank” relies on professional know-how to create a surprising but presumably safe spectacle. The humor comes from the contrast between the expected sweetness of a birthday cake and the sudden, theatrical “explosion.”