Regarding your search for a PDF:
Regarding the "Álbum" term: In the context of European comics, "Album" refers to the standard hardcover format (usually A4 size, 48-64 pages). Les Melons de la Colère was released in this standard hardcover format.
Since the album does not exist, any website offering a "les melons de la colere pdf téléchargement gratuit" is either: les melons de la colere pdf %C3%A1lbum
Do not download any "PDF" from non-verified sources. No legitimate author or publisher has ever claimed this title.
To close the loop on your search:
Enjoy the hoax. Share the legend. But do not waste your time looking for a download. The real Melons de la Colère is the friends we made (and the clickbait we fell for) along the way.
Final advice: If you want a surreal French comic that does exist, start with Les Idées Noires by Franquin. No melons, but plenty of wrath. Regarding your search for a PDF :
Have you seen a fake cover or a scan claiming to be from this "album"? Share it on r/lostmedia – but add a big "HOAX" label. The myth is more interesting than any actual PDF could ever be.