Here's the idea, in the haze roams a praying mantis that has been affected by that weird fungus that's all over the place there. He attacks on sight with slashes, lunges, and stabs with his "scythe like" arms and occasionally flies up for a moment to come crashing down with a huge slashing attack. The loots that comes from killing the mantis could be two mantis arms or something and the player could craft those into mini hand scythes that works with the "assassin" mutation or a big two and handed version that works with the "javelineer" mutation. A possible name for the boss could be the "Haze Reaper" and the name of the weapon could be the "Haze Reapers' Right/Left Hand".