Wezen (the double-headed kangaroo)
A constellation in the Discworld sky. Although if this has been a constellation for as long as anyone can remember, it begs the question of how a species native only to Fourecks was well enough known, prior to the Great Wet, for a constellation and a star sign in astrology to be named after it.
The Compleat Discworld Atlas says that Wezen is composed of thirteen stars and that drunkards are conceived under this sign. It is apparently a good omen for prisoners in jails such as the Tanty who are contemplating excapes: if Wezen is seen in the skies over the exercise yard, going over the wall is well aspected.