Crops up—sometimes overnight—in the most unlikely places. Does what it says on the tin. Cue the Devo.
Deep in a cavern, adventurers are forced to abandon the body of a slain comrade, opting to forge ahead in hopes of finding enough treasure to raise their dead friend. Despite covering his body with a cairn, when they return they find a strange lily-like plant has taken root in it…a plant that suddenly attacks when they come too near.
Crotchety farmer Turk Whallot was determined to never let anyone take his land. His independence ultimately killed him when he tried to exterminate a weedwhip without aid. Putting his affairs in order (or claiming his valuable land) will be difficult, however. The weedwhip still dwells on the property. Its fishy odor has attracted several giant flies that are now breeding maggots. And Turk himself is so dedicated to driving off intruders that his corpse will animate to attack them (as a zombie if they are merely sorting through his affairs for his kin; as a wight if they are claiming his property as their own).
A young otyugh trundles into the town market (much to the horror of all the residents), repeating such phrases as “Help,” “’Ventures” “Swords,” and “Bad plants.” For the moment it is harmless, thought it will quickly become agitated if ignored for too long and violent if attacked. A patch of weedwhips recently took over the otyugh’s favorite offal pile, and during molting season the creature’s skin is too soft to protect against the plants’ whiplike tentacles. Having had its life spared by adventurers before, the intrepid otyugh seeks their aid now.
—Pathfinder Bestiary 4 276
If you’re looking for the weasel, it already weaseled its way into our monster countdown here.