Featured in the very first episode of Weird World, the venom of the Mongolian Death Worm is highly corrosive. It is so strong that it can dissolve metal. V.V. Argost used the venom, shaped in marble-sized spheres, to attack the Saturdays in "The Kur Stone: Part Two".
Although the venom was seen throughout the series, the actual worm is only seen in the video game.