her bathroom is filled with black mold, the movie is actually a Jacob's ladder scenario. The black mold has infested her vagina - deaf chicks don't understand douching or probiotics in the 1950s, so her vagina is a YEAST MONSTER and every time she takes a bath it triggers hours of orgasms. The entire movie takes place in her fevered orgasm mind as she is dying in the bathtub, its a metaphor for how ummmmm white people treat the planet or something
Guillermo del Toro is a genius for capturing the visions of someone in the throes of death-orgasm, or death sploosh as Rafie would say