The spikes distinguish it from a mace, which can have flanges or small knobs. It can also come in two forms, where it either has a handle like a mace or the ball being attached to a chain which is in turn attached to a handle like a flail.
In Mortal Kombat
The Morning Star is the Cleric of Chaos Havik's weapon of choice & style in Mortal Kombat: Deception and Mortal Kombat: Armageddon. It is similar to the mace used by the demon sorcerer Quan Chi in Mortal Kombat 4. The most noticeable difference however is the design of the handle and shaft. Alongside the spikes of the Morning Star being longer but slimmer.