The Rock Chucker's enhancement disperses any potion poured into its reservoir around the impact point.
Carl initially mistakes Poison Cloud for a fixed, self-contained enchantment. He discovers a cup on the side of the sling that accepts liquid poison or potion and substitutes it for the default payload.
When the trebuchet launches a rock, the enhancement converts Mordecai's anti-Creeper mixture into a cloud above the target. Rain spreads rather than spoils the weedkiller, and the Creeper dies seconds later.
A small reservoir on an enchanted sling that produces a colored cloud around a projectile's impact.
Poison Cloud is the hidden delivery capability that makes the captured siege weapon strategically decisive.