The Rumor Weed is the main antagonist in the VeggieTales episode, Larryboy and the Rumor Weed.
She isn't actually just one weed, but a whole army of super strong, property-wrecking, rumor spreading weeds, all under the rule of their leader, The Mother Weed. They were destroyed when Junior Asparagus and Laura Carrot spread nice words about LarryBoy's butler, Alfred, who was being a dangerous robot and having others believe it.
The Weeds are extremely destructive and powerful, as normal tools that would normally destroy a weed have no effect on them, and according to Alfred, the Weeds can crumble sidewalks and destroy brick walls. Enough of them spread out in the city that Mayor Blueberry was worried that their property values would plummet, and their homes would not be worth anything. The roots of the Weeds went underground, in the tunnels and sewers in Bumblyburg, all connected in a hive-mind with The Mother Weed. The Weeds need to have a lot of energy, but do not photosynthesize. Instead, they feed on rumors themselves.
The Rumor Weed is a green weed with yellow hair, red lips, a pearl necklace, and pink shades (sometimes purple in LarryBoy and the Bad Apple).