Great Power

The Great Power was an Earth mushroom known to the Voords. It grew in a South American jungle, could bestow brain-enhancing powers, and was used by Inca priests. When the Daleks learned of it, they pretended to form an alliance with the Voords in order to acquire it so they could outwit any enemy. After they destroyed the Voords, the sole survivor, the Chief Voord led the Daleks to the mushroom, knowing that was poisonous to them. Although the Great Power did indeed increase their brainpower, allowing them to shoot down a fleet of Earth fighters, they all died shortly afterwards. (PROSE: Doctor Who and the Daleks)