Gameplays in general are RNG-heavy who knows if the Estoc you carry now will be replaced by a broken long sword, or even worse, something unusable, before a difficult boss fight. The challenge involves completing the game with the equipment you currently have, and changing it every time you see a drop or another item, if possible. This ties into a challenge called the “Use What You See”, popularized by Twitch streamer LobosJr.
A staple for Souls mod runners, the Randomizer mod will randomize the items found throughout the game, from items on the ground, to chest loot and even enemy drops.