A wand-like alien device used by Korob and Sylvia on Pyris VII to turn their thoughts into solid reality, including a castle, a giant cat and their own humanoid bodies.
The transmuter appears in the episode Catspaw. Korob and Sylvia, explorers from another galaxy, use it on Pyris VII to draw images from the human subconscious and make them real, producing a haunted castle, witches and dungeons.
The device amplifies and focuses the will of whoever holds it. Sylvia uses it to control members of the landing party and to change herself into an enormous black cat, while becoming ever more absorbed in the physical sensations of her borrowed body.
Korob, alarmed by her cruelty, frees the prisoners and is crushed. Kirk takes the wand and smashes it, and the castle disappears. The two aliens are left in their true form, tiny and frail creatures that cannot survive and dissolve within moments.