I forgot what mod it was, but it did have prone. It was kind of wonky, though. When you'd go prone, the mod would randomly start making you float. Also, you had the hitbox of crouching. So, you could be prone, and get hit in the "head hitbox" 3 feet above you. It was pretty stupid. Honestly, I think it was Survival Zombies or some shit like that. I really can't remember. All I remember was that it had zombies, demons, and mutants.