write bad fanfic of your own work (is that possible?)

Lyda Morehouse wrote fanfic of her own work. Someone asked her, since she was the creator of the world, wasn't anything she wrote there canon by definition? She said no, because she didn't think the fic stuff "really happened," it was too out of character for at least one of the characters. Thus, she was declaring it fanfic, rather than canon.

So sure, you can write fanfic (good or bad) of your own work.