The ancient gorilla greegree is made from a monkey skull, which can be looted from zombie implings. When wearing this greegree on Ape Atoll or some places in the Ardougne Zoo, the player will turn into a gorilla with a blue face. This greegree is the rarest because the required bone can only be obtained by looting zombie implings and their jars. This item has existed since Monkey Madness was released, but was not obtainable until zombie implings were released on 22 February2010.
The chathead of the blue-faced ancient gorilla is that of an Elder Guard rather than one with a blue face.
The different greegrees can be combined by using one on another. This adds both of the greegrees to a list that can be accessed via the Swap option on any of the greegrees that the player owns, and in the process deletes the greegree that was used on the other. The greegree can then be turned into any of the greegrees by selecting it in the list. The greegree cannot be swapped into another while it is equipped, but it is possible to equip another to change forms.