I don't know what I did to make my fairy sim get stuck, because I hadn't used MOO - but she got stuck either upside down, and/or in the floor. All I could see were her wings and plumbob, and when she cooked the cooking utensils were upside down and didn't match up with the stove and bench.
Anyway, first I tried resetsim, and that didn't work. Then I tried MOO, but there was nothing there to grab. I tried TCE and teleporting her, and that didn't work either. Finally I sent her to bed, and voila! She's above the ground again!