The action is ennui and anxiety; the setting is rock, ooze, dirt, steam, hair, filth, and reptilian forms; the plot is a Rorschach test. Lynch admitted his film was based on his fear of becoming a father, and never has parental dread taken a more nauseating form. What's falling onto the stage when the Lady in the Radiator is performing? What is Henry pulling out of his wife's body in bed? These things sure look sperm-like.
On my first viewing in more than thirty years, knowing what to expect, I found myself far more amused than horrified. If your mind tilts that way, you can take Eraserhead as uproarious satire, with its frontal assault on normality. Remember General Jack Ripper's anxiety in Dr. Strangelove about pollution of our "precious bodily fluids?" Well, here those fluids are spilling all over the place.
The film's unique cosmology is very "me generation": the universe is contained inside your head. So go ahead, blow your mind. Be amazed at the low-budget special effects that resemble a high school chemistry experiment epic fail yet are scarier than most of today's too-perfect CGI. It's a riveting experience, though in any party of four or more at least one viewer is apt to loathe this cult classic. Weak stomach warning: avoid quail or Cornish hen for dinner that night (or perhaps skip dinner altogether).