Zombie superheroes!
If Marvel wanted to go the horror route, one detour could be a version of Marvel Zombies, a 2005 limited series set in Earth-2149, in which a virus transforms the world’s superheroes into the undead. It’s a concept far too weird to ever make it into the ‘prime’ MCU continuity — but the multiverse could be the perfect loophole. Zombie Spidey? Would watch.