A weeper was an animate, carnivorous plant.
One weeper plant was "Beauregard" (also known as "Gertrude") that was kept aboard the botanical section of the Enterprise by Lieutenant Hikaru Sulu. It was a tall (3-foot) hollow rooted tube, from which pink flower petals could extend and retract like a grasping hand. The plant would purr in the presence of those it liked, but was capable of shrill, high-pitched cries when frightened. (TOS: "The Man Trap")