Insanium is a rare radioactive metal almost exclusively found in asteroids.
The radation the metal emits distorts the brainwaves of sane beings and renders them momentarily braindead. Prolonged exposure leads to death.
Only insane men can handle insanium without suffering ill effects. Even machines coming into close proximity to the material malfunctions and shuts down.
Insanium is one of the only known things that can harm Stalin.
Radam Smetenskij has gathered the only known pieces of Insanium, through methods unknown. He always carries a piece of Insanium with him, sealed in a lead-lined box to avoid killing everyone in his vicinity by mistake.
In Castle Börran, Radam's throne is also made out of pure Insanium. This has made audiences with Radam difficult, as visitors have to wear protective suits or convince Radam to talk to them in one of the other nine hundred and ninenty-nine rooms of the castle. The Insanium throne has proved to be a boon when dealing with assassins, however. Radam simply shoots them with his Beard Beam to rip a hole in their protective suits, and then lets the radiation finish them off.