A practitioner claims to give physical, visible form to something otherwise unseen during a seance, and the claim is specifically that she is spending her own vital energy to do it, an effortful expenditure rather than passive channeling. This is contested ground by nature; spiritualist claims of physical materialization were disputed in their own era and remain disputed now, and any confident account of what actually happens in such a session would overstate what is actually known.
The active, expending quality classically assigned to this final decan fits the claim being made: whatever is happening here, if anything is, is described as costly rather than effortless. Pisces sits closest of any sign in this set to the border between the seen and the unseen, and this degree is its most direct engagement with that border, the idea that consciousness or desire might, through enough vital expenditure, take on some form of physical presence, for good or ill depending on what is actually being given form.
Its weaker, and more likely, reading is exactly what the contested nature of the claim already suggests: apparent substance produced through misdirection or self-deception rather than through any genuine transfer of force.