The ornamental skulls worn by random groups of Muties are those of an ancient, small, bat-like creature that once lived on Anomaly. The diversity of these “mini skulls” varies wildly, but are believed to be from the same species. Their cranial remains are inexplicably coveted by the Muties. They are an archaeological rarity, true, but the greater mystery is the Mutie attraction in their collection. They are, in fact, the closest thing the Muties have to any system of currency (the other being food).

The skulls remain the only commodity of value the Muties have they did not kill themselves (unless they murdered a fellow Mutie for their clutch of skulls). The Moncs have since admitted some of their best intelligence on Erebos was gained by bribing carefully selected Muties (those seen as most pliable to greed over fear) with these miniscule bone collections.

Some of the small skulls sported by the Muties are strikingly similar to the current dominant races… Whether this is a pre- or post-adaptive cycle of the bat race’s evolution (or a skull-broke Mutie acquiring small skulls from stomach turning sources available today) is not known.