unkempt fractal
Basically just take spys Tranquilizer gun and make it into a sniper weapon. You can scope and make it do 50-100 damage on headshots. 20 on body shots. It would slow down a player for like 2-3 seconds. And sniper would have 5 shots before he has to reload.
rustic cobalt
Not particularly into this idea myself since I'm a bit of a tranq hater, but would this still be a projectile weapon or a hitscan one?
distant fjord
ehh... at that point why dont you just headshot them?
iron flax
Five Hundred Tranqdarts