Left skull half

The Left skull half is part of the Skull sceptre. The left skull half is used with the Right skull half to obtain a Strange skull. It is dropped by Ankous on the fourth level of the Stronghold of Security. The left skull half can be traded and withdrawn as a noted item from the bank. Either skull half is more difficult to obtain than the other parts of the sceptre. The skull half looks like half of a minotaur skull, while, oddly, the right half would look more like an Ankou's skull, and is dropped by minotaurs. This tends to be dropped with a Battlestaff.

Wearing any level of Varrock armour when slaying ankous will increase the chance the monsters will drop the left skull half.

Considering it is the "Left half" of the skull, it is actually the right. It is the same with the "Right half" of the skull.