Warpstone

Warpstone is a fictional mutagen found in the Warhammer world, and also in the Warhammer 40,000 universe during the first and second editions. Humans and most other races in Games Workshop’s campaign game Mordheim refer to it as Wyrdstone.

Warpstone is solidified Dark magic (Chaos Energy, aethyr), and as such it holds tremendous transmutatory and alchemical powers. In its unrefined form, it is a stone that emits “blackness”, appearing to swallow all light from its surroundings, and so creates a patch of darkness around itself that makes it impossible to see its exact shape. It is sometimes described as “still emitting its own green glow”, which would result in a rather complex optical illusion. Everyone in the vicinity of a lump of unrefined Warpstone for more than a few hours is in danger of gaining a mutation. Refined Warpstone is considerably less dangerous. It takes the form of translucent crystals or a grey powder that must be ingested (or otherwise enter the body) to even get a chance of causing any mutations. Its long-term effects, though, seem to be similar to those of some psychoactive drugs.