So, I saw Bulbapedia's page on Comatose states what affects this "sleeping" Pokemon. Apparently, Hex does double damage to it. But it's immune to Hex, you say? Well, not when you use a move that changes its type, like Soak, then it does double. So that makes me think...
It also says it is susceptible to Nightmare. But can that really be, when Komala is a Normal type? Is Normal immune to Nightmare? I've honestly never encountered that circumstance, since you don't see Normal types in Ubers (Darkrai). Or would it require Soak?