I won't be able to make a new post tonight, so I'll write out an excerpt from Porius instead.
But Morfydd now began to suffer from a nervous trouble that was one of the very few things that could -- and it only happened very rarely -- keep her from going to sleep the moment she desired to do so. This was a tendency for some physical object, like the horn-cup rimmed with silver out of which the Henog had spilt that wine, some object associated with an accident, a tribulation, a blunder, a sacrilege, an impious deed, or simply with a malicious and vindictive deed, to obsess her brain so that the more or less thick darkness about her bulged and bellied and billowed with the object in question and she would feel -- such was the horrid fancy -- that this accurst devil of an ordinary object was bent on persecuting her and with this purpose went on and on projecting itself into her inmost being, into her flesh, so it seemed to her, and into her consciousness too, until her soul felt like a mouse, surrounded on all sides by grinning cats.
"Bulged and bellied and billowed" reminds me that he liked Rabelais. "To read Rabelais is to gather, as if from the earth-gods, spirit to endure anything [...] What he has the power of communicating to us is a renewal of that physiological energy, which alone makes it possible to enjoy this monstrous world." (Visions and Revisions: a Book of Literary Devotions)