The secondary object (42355) Typhon I, discovered 2006 Jan. 20 by K. Noll, W. Grundy, D. Stephens and H. Levison using the Hubble Space Telescope, is named Echidna for the mother of all the major monsters in classical Greek mythology. Half nymph and half snake, Echidna lives, immortal, in a deep cave called Arima.