Malus, the ship's mast:

An ancient constellation that was once part of the great ship, Argo Navis, along with Carina, the keel; Puppis, the deck; and Vela, the sail. Malus is no longer recognized as a separate constellation, its stars have since been incorporated into the constellation of Pyxis, the compass, created by French astronomer Nicolas Louis de La Caille between 1750 and 1754.