Right skull half

A Right skull half is one of 4 parts needed to make a Skull sceptre, and can be found by killing a Minotaur on the first level of the Stronghold of Security, the Vault of War. These minotaurs can be either level 14 or 52 and are not aggressive. It is combined with Left skull half to make a Strange skull. It cannot be traded, bought or sold. It is a fairly uncommon drop, as are the other pieces of the Sceptre. It seems to have the highest drop rate of any of the pieces of the Sceptre. You can also get more than one skull half at a time, without using the drop trick. Interestingly, the skull half looks like that of an ankou, while the left skull halves dropped by Ankous seem to be minotaur skulls.

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

Trivia

 * Although this item is called the "right half" of the skull, it is actually the left half.

Right skull half