They lay dormant and wait for some unsuspecting curious prey and snap shut on them, devouring them. They can chase as well, awkwardly hopping after their prey. Some have some features to them when they come out of hiding: teeth/tongue, eyes, and/or arms. Never legs, though.
Migration into the Mystics has made their enchantments more permanently infused, so these creatures can exist where magic does not. The infusion has also enabled them to modify themselves but only in a simplistic way. (ie they can change up their form from box to bag. They can't change color/design or size at will.)
What began as an item enchantment became sentient in the worst way.
They tend to stay in the same vicinity as where they were created, but can migrate slowly overtime. They prefer quiet places where prey are to feel comfortable or curious with their existance, and are unlikely to be found where crowds will be as their feeding method will be alarming and draw too much attention to itself.
Mimics are stronger than they appear to be and are quite resiliant which may discourage attacking it back; however they are still just whatever they are made of (hard wood, metal, burlap, etc) and will break accordingly.
Varies, but no bigger than 4ft in height
Varies, no heavier than 150lbs. Correlates with Height; so you will never encounter a tiny box weighing 150lbs and you will never encounter a large box weighing a few ounces..
Carnivorous. Mimics of all types enjoy anything alive and moving. Used to eating sparingly, they can go a while (up to a month) without food, but ideally 2 1/2 lbs of food per pound of body weight is the way to go for them.
Aesexual. When reaching its maximum size it will 'shed' anew and a second mimic is then active and the original will be halved in size. The new mimic will start small as a jewelry box. A mimic will be able to reproduce once in a human's life time.