cursed mask

I have an idea for a mob that is simply decoration, but can pop off the wall it is hanging on and attack entities that are not the person that placed it. it could drop a placeable version of itself when it dies, providing the uses stated above. it could be crafted together with an emerald to create a non-hostile version. finally, it could look different depending on where it is placed (tiki-like in jungle/beach, pharoh-like in desert, statue-like in nether, and a blob in the end).