Armor Stand Golem

My son came up with a great idea for a mob. He wants to invent an Armor Stand Golem, where you equip the armor-stand with a full suit of armor and weapons and shield, but the helmet must be lit jack-o-lantern that makes it come to life. When alive it has the same color and armor and weapons that you equipped it with - it becomes a mob that defends your village and attacks any hostile mobs near your house. If you're holding a jack-o-lantern in your hand instead of a weapon it follows you around. Rain makes it rust and oxidize over time, and you can't repair it ever. It eventually breaks and turns into two blocks of obsidian.