This is the adjective relating to teleplasm, another word for ectoplasm, the supernatural substance that’s said to exude from the body of a medium during a trance.
In one remarkable image, the teleplasmic larynx sits on her head like a caul, while a thin but perfectly visible thread runs into her ear; in others the miniature teleplasmic mass rests on her shoulder, connected to her by a thick cable that runs into her nose.
Dumbstruck: a Cultural History of Ventriloquism, by Steven Connor, 2000.
Teleplasm is rather younger than ectoplasm, starting to be recorded only in the middle 1920s. It was obviously modelled on the latter, which starts to appear a couple of decades earlier. Both are based on Latin and Greek plasma, something formed, moulded, or simulated. This is the source of the ending -plasm that refers to living tissue in words such as cytoplasm and protoplasm (ectoplasm, in another sense, also belongs with this set, since it is the scientific name for the more viscous, clear outer layer of the cytoplasm). Ecto- means outside, so ectoplasm frequently refers to a living tissue that is supposedly formed by the medium outside her body; tele- here means much the same, though its root sense is something happening at a distance.
A recent appearance in fiction is in the 1998 Hugo Award-winning SF novel by Connie Willis, To Say Nothing of the Dog, or How We Found The Bishop’s Bird Stump At Last, described in one review as “a time travel story, a mystery, a romance, and a screwball comedy: think Bringing Up Baby meets Three Men in a Boat”, in which a fake seance occurs:
”How wonderful!” Mrs. Mering said. “Do come sit down. Baine, pull up a chair for Madame Iritosky.” “No, no,” Madame Iritosky said, indicating Professor Peddick’s chair. “It is here that the teleplasmic vibrations converge.” Professor Peddick obligingly changed chairs.