A Creature you can see takes a number of d8s of force damage equal to the number of chairs you can see from your seat in real life. Additionally, you gain a number of d8s of hit points equal to the number of chairs you can see from your seat, with excess hit points becoming temporary HP. Additionally, again, you get an advantage on all Charisma checks as long as you explain how you do it, and it has some very cheesy pun woven into it in some way until  the spell ends.