Endodroids are artificial entities composed of a metallic solid with a large number of protons per atom, called droidium. Endodroids are designed typically for infiltration and assassination jobs. Their ability to change shapes makes them ideally suitable for the job, and consequently, extremely dangerous. Fortunately, endodroids are easily detectable using an unmodified datacorder, and can be restrained for a limited amount of time by freezing, typically with liquid nitrogen.