Stone Mask

The Stone Mask (石仮面) is an aztec artifact only known by a vampiric cult hidden within the Aztec Empire. The stone masks were designed by Kars as an initial attempt to give his race the ability to withstand sunlight. However, they were "only" powerful enough to turn humans into vampires. On the back of the Stone Mask possessed by George Joestar I, there is something written in an ancient language. It is unknown what it means nor if it was written by Kars or the Aztec.

Story
During the mid-to-late 19th century, the mask was excavated by humans and later the subject of research by Jonathan Joestar, who was unable to understand its purpose and was only able to come up with speculative theories. These theories attracted the morbid curiosity of Dio Brando, who believed it to have been an execution item that he could attempt to use on Jonathan, and after testing it on another human, realizes that it transforms them into vampires. During his struggle with the Joestars, Dio used a hidden blade to stab George Joestar I in order to activate the Stone Mask and become a vampire. This would start a long grudge between him and the Joestars.



Abilities
The mask is triggered when it is touched by human blood. It will then extend tendrils of stone from its edges, piercing the wearer's skull and brain. The tendrils are meant to precisely find and trigger certain points in the brain in a fashion similar to acupuncture, and from thereon release the wearer's potential strength. This surge will give the wearer vampiric powers and superhuman strength, but also render the body effectively "dead" and unable to contain life, such as direct sunlight or ripple. When fitted with the Red Stone of Aja and exposed to light, the stone mask has the capability of piercing a Pillar Man's skull. In this case, the mask unleashes an ironically retrograde effect, in which pillar men are completely immune to the Sun, and have the ability to use the ripple and morph their bodies on a cellular level into any pre existing creature.

Trivia

 * As one of the most famous items in the franchise, the Stone Mask has appeared in several games:
 * In JoJo's Bizarre Adventure: Heritage for the Future, as part of the "Stand Crush", when one of the players has it's Guard Gauge broken by the opponent, the Stone Mask briefly appears on the screen.
 * In JoJo's Bizarre Adventure: Phantom Blood (PS2 Game), before every match begins, the Mask gains life for a short time and it's tentacles comes out, announcing the episode start.
 * It appears in Jojo's Bizarre Adventure: All-Star Battle as the representing item for PART I arc in several trailers and Story Mode.
 * Various games in the Castlevania series have an item called Stone Mask (sometimes called Jade Mask), which, according to in-game descriptions, were used in ancent rituals. This is a clear reference to the Jojo series. Appropriately, vampires are a central element of the Castlevania universe.