The Trap Door is a children's claymation-style animated series, shown in the United Kingdom in the mid-1980s. It was created by Terry Brain and Charlie Mills.

The main character, Berk (a short blue creature), his pet spider Drutt, and his friend Boni (a talking skull), live in a castle in "the dark and nasty regions", where Berk serves The Thing Upstairs (who never leaves his room, and is consequently never seen, although his bellowing voice is frequently heard). In addition, Berk must guard the trapdoor in the floor of the servants' quarters, which leads to dark and mysterious caverns from which, every episode, something will emerge... Though mostly hostile or mischevious, occasionally a helpful or friendly creature did emerge, the large red creature named Rog was one example.

The series ran for two seasons and numbered 40 episodes. Each episode was around five minutes long. All the character voices were provided by Willie Rushton.

Although selected episodes of the series were available on various videotapes in the UK at various times, only a rare double videocassette released in Canada at one point actually contained every single episode. It was not until 2005 that all the episodes were finally made available on DVD in the UK.

The television series spawned a video game in the mid-80s called The Trap Door and a sequel called Through The Trap Door. These games (available for the ZX Spectrum and the Commodore 64) probably introduced nearly as many people to the quirky blue creature as the series did. They can now be played on a modern computer system using various emulators.