Bestiary part 1:

Shimmers are slow moving creatures that contain a luminescent, volatile fluid inside their fleshy membranes. It is not quite known how the creatures see, but they seem to be able to sense objects that contain large amounts of metal alloys. When posed with such an object, the Shimmer will attempt to latch itself to the object and empty its insides onto its target. It is unknown quite why the Shimmers react this way, for the Shimmer kills itself in the process...