Person · short entry
Mersenne Prime
The only Earth Cat, and the only non-Rump of any kind, ever given a true Rump Factor: 0.6.
Mersenne Prime is the only Earth Cat ever given a Rump Factor. His score was 0.6.
The cats of Earth are Non-Rumpish Felines, who by definition have no Rump Factor, and Mersenne Prime is the one exception. His is a true Rump Factor, the only one ever held by a non-Rump; the only other non-Rump ever scored, Professor Zanzibar, was given an honorary 0.5 that carried no real weight.