The Star-Slaying Harpoon

Turn a normal Harpoon into "The Star-Slaying Harpoon" and Launch it at a target, doing 3d6 Piercing damage, if the harpoon hits its target it embeds itself into their body at the beginning of your next turn it will pull them up to 15 ft. closer to you as it removes itself from their body, if the target is a celestial they have a Vulnerability to Piercing damage until the harpoon is removed from their body. 

"Don't you know? This harpoon was made to get vengeance upon a celestial who wronged me. And while I can't use it against that filthy celestial, my old friends definitely will." - Luca Nebulas, The Distorted One

When this spell is Upcast it does 1d6 additional piercing damage and can pull the target 5 additional ft. towards you.