In the District of Dofft there are Two Offt from Dr. Seuss's Sleep Book who are sleeping aloft off the ground levitating they wrote signs reminding someone to please pull their tails at 8 A.M. to take them up.

The female creature hanging from the tree by her tail from the beginning of the book that has the title of the story and who is the narrator of the book on video tells the viewers that she weighed one of them and has found out that the Offt is so light that he weighs minus one pound.
Dr. Seuss's Sleep Book (185)
Dr. Seuss's Sleep Book (186)