See those red marks? (Of course you do–they’re dang hard to miss).
What do they look like?
Like tiny bolts of lightning, actually.
Believe-it-or-not, they are discharges of static electricity on the film.
This is what happens when you shoot high speed films like Cinestill 800 in dry climates like Alberta. It typically occurs when one winds the film too quickly. (And, incidentally, part of the reason why most cinema films have Remjet backing on them, as they move at 30-60 fps through the motion picture camera).