Weeper

A weeper is a type of animated, carnivorous plant. The plants were known to purr in the presence of someone it felt safe with, but would make high-pitched noises when it became frightened.

In 2266, a weeper (nicknamed "Beauregard") was kept in the botanical gardens aboard the USS Enterprise, and was studied by Lieutenant Hikaru Sulu. (TOS episode: "The Man Trap").