I have seen every single episode of AT but the thing is that I didn't watch them in the right order. This will sound totally dumb. Did the mushroom bomb or did a comet cause the creation of Ooo? Did the mushroom bomb cause the creation of the Lich or vice versa? Can you PLEASE post, in the simplest explanation you can, a linear timeline of how many comets and mushroom bombs have happened in AT (including a separate line for the alternate dimension/s)?