An organic seed-spike that the carnivorous plants spit at potential food or seed carriers.”— In-game description, Fallout 2
These thorns are spat by spore plants at foes, and can be collected off the ground. They are weak and worthless, best to be left be. However, unlike rocks, they are weightless, so the only reason not pick them up is to not have a cluttered inventory.
Thrown by spore plants.