A chasing staff is a kind of polearm

Pole weapon

A pole weapon or polearm is a close combat weapon in which the main fighting part of the weapon is placed on the end of a long shaft, typically of wood, thereby extending the user's effective range. Spears, glaives, poleaxes, halberds, and bardiches are all varieties of polearms...

 that was used in the Middle Ages

Middle Ages

The Middle Ages is a periodization of European history from the 5th century to the 15th century. The Middle Ages follows the fall of the Western Roman Empire in 476 and precedes the Early Modern Era. It is the middle period of a three-period division of Western history: Classic, Medieval and Modern...

 of Europe

Europe

Europe is, by convention, one of the world's seven continents. Comprising the westernmost peninsula of Eurasia, Europe is generally 'divided' from Asia to its east by the watershed divides of the Ural and Caucasus Mountains, the Ural River, the Caspian and Black Seas, and the waterways connecting...

. It consisted of an iron-shod staff some 10-12 feet long, with a spike on the butt end and a metal head at the other. The head was made of a large, flat 'blade' which had a few small protrusions coming off of the top and back. It resembled an early halberd

Halberd

A halberd is a two-handed pole weapon that came to prominent use during the 14th and 15th centuries. Possibly the word halberd comes from the German words Halm , and Barte - in modern-day German, the weapon is called Hellebarde. The halberd consists of an axe blade topped with a spike mounted on...

 or bill

Bill (weapon)

The bill is a polearm weapon used by infantry in medieval Europe.The bill is similar in size, function and appearance to the halberd, differing mainly in the hooked blade form...

.