People have been doing unbelievable things in Dark Souls for years. Speedrunners have finished the game without taking damage, without leveling up, and without taking damage or leveling up. One challenge that's always stood out to me is the idea of finishing the game without rolling, not just because every cell in my body vehemently rejects the idea, but because the opposite—exclusively rolling—sounds hilarious and much more fun. Thanks to modder notaprofi, creator of the newly released Rolly Souls mod, PC players can now attempt just that.
As notaprofi explains on Nexus Mods, Rolly Souls disables walking, jogging and sprinting in the original Dark Souls. You can only move by rolling. Well, that and via the advances and shuffles of attack animations, but rolling is your bread and butter. It sounds pretty silly, and it most certainly is, but it would also make managing your stamina much harder, so I reckon it'd be a pretty difficult way to play. The only caveat is that some human characters, like Havel the Rock or NPC black phantoms, can also only move by rolling. Then again, 1v1 Dark Souls fights are pretty much constant rolling anyway, so you might not even notice the difference.
Incidentally, Rolly Souls reminded me of one of my all-time favorite Dark Souls builds: Captain Tippy-Toes, a tanky character who exclusively used the hefty Great Club. By exploiting the Dark Wood Grain Ring's ridiculous cartwheel rolling animation, I was able to spam the Great Club's toe-smashing rolling attack, hence the name. Sadly, Captain Tippy-Toes was forever ruined when the Dark Wood Grain Ring was nerfed so that it only changes your roll when your weight is incredibly low. But thanks to notaprofi, his spirit will live on in Rolly Souls.