We draw what happens when your character takes the potion! For example... Say there is a "Siren Potion" (there isn't, at least not yet, but it sounds interesting so I might make one) and you pick a character of yours to take the potion. After paying (or if it's in the Free section then you wouldn't be paying) we draw the effects the potion had on the character. So for example if someone sent in a normal human character to drink it then they might end up sprouting scales.