Triffid

Triffids were dangerous plants. (PROSE: The Secret in Vault 13) In 1964, when Sarah Jane Smith said she sort of believed Maria Jackson's warning that Westport pier wasn't safe, Andrea Yates replied that Sarah'd believe that a Triffid was going to come and get them. (TV: Whatever Happened to Sarah Jane?) When Sarah Jane told Gita Chandra that her contacts were not usually interested in flowers, Clyde Langer quipped "unless they're Triffids." (TV: Prisoner of the Judoon) The potted plant in the Director-General's office was a Triffid of shoulder height. (PROSE: Not So Much a Programme, More a Way of Life)

Behind the scenes
Triffids are fictional main antagonists of 's novel The Day of the Triffids. However, it is not stated in-universe whether they are fictional in DWU.