Nocturnal Golem

This golem would spawn in flat areas like plains and meadows. They would act as statues during the day, similar the copper golem, but at night time their eyes, as well as their cracks would glow and would start to move around and eventually attack you. It's fast and strong but if you place a light source near it, it will freeze. They can only be killed with a pickaxe and at night their is a chance it will drop useful items that could be used as utility but I will let you decide.