Japanese knotweed

Japanese knotweed was a plant.

In at least one universe, it became an invasive species in the British isles. Jenny Bainbridge was made to watch a public-service announcement video about it at school. She found it dull that it was “just” a fast-growing weed, and not an actual evil plant able to move on its own accord and ensnare victims. (PROSE: The Genesis of Jenny Everywhere)

In another universe, that happened - magically transformed knotweed was used by Yaoi Boy to tie up Jenny Everywhere. Whether it actively pursued people on its own was not specified. (PROSE: Return of the Puritan Streaker)