In 1975, Professor Jack H. Hetherington of Michigan State University wrote a physics paper. He sent it to a colleague to look over before he sent it to Physical Review Letters. The colleague told him that it was a publisher's rule that words like "we" and "our" could not be used in a paper that had only one author.
Instead of retyping the paper, Hetherington added his Siamese cat, Chester, as a coauthor. He was clever about it though. Instead of just writing "Chester," he put "FDC Willard." The FD came from "felix domesticus." The C stood for "Chester." And the Willard came from Chester's father's name.
The ruse was up though when a student came to campus and asked to talk to Professor Hetherington. When he was unavailable, the student asked to speak to the other author, Willard.