In a funny way, the major studio sci-fi blockbuster Dune (1984) is the weirdest thing David Lynch ever did - and this is a man who reimagined tragic small town teen Laura Palmer as messianic figure dreamt into existence, in the form of a golden orb, by a levitating Giant renamed the Fireman.
Directed early in his career without final cut, showing something of a mercenary streak he defined his latter career by abandoning, Dune is almost monumentally silly despite or because of its earnest, by turns whispery and shouty dialogue, camp costuming, and naff special effects - all of which converge to smother the major plot stakes in hysterical cheese. Mired in development hell, where it should have stayed, this was a hellish experience for Lynch, who almost immediately distanced himself from the work. Given the extent to which Lynch did so, this is arguably Lynch's most important film. Inarguably, it is his worst.
Lynch later rose to (or reclaimed his) arthouse credibility by filming the un-film-able, literally dreaming up sights and sounds only his ingenious mind could devise and transpose to the screen.
This was Lynch filming the un-film-able, a ludicrously dense tome condensed into an incoherent mess, in the worst possible way.