Shapechanger. The mimic can use its action to polymorph into an object or back into its true, amorphous form. Its statistics are the same in each form. Any equipment it is wearing or carrying isn't transformed. It reverts to its true form if it dies.
Adhesive (Object Form Only). The mimic adheres to anything that touches it. A Huge or smaller creature adhered to the mimic is also grappled by it (escape DC 13). Ability checks made to escape this grapple have disadvantage.
False Appearance (Object Form Only). While the mimic remains motionless, it is indistinguishable from an ordinary object.
Grappler. The mimic has advantage on attack rolls against any creature grappled by it.
Pseudopod. Melee Weapon Attack: +5 to hit, reach 5 ft., one target. Hit: 7 (1d8 + 3) bludgeoning damage. If the mimic is in object form, the target is subjected to its Adhesive trait.
Bite. Melee Weapon Attack: +5 to hit, reach 5 ft., one target. Hit: 7 (1d8 + 3) piercing damage plus 4 (1d8) acid damage.
Corpse is an object.
So is a mannequin,
So if you find old enough mimic it could become NPC.
Edit: The older they are the more intelligent they become. All lore based.
I love these things for some reason!
good question
Not sure if you’ve already got a response to this; yes, but no. Mimics can only polymorph into medium or small objects. HOWEVER, Hoard Mimics can morph into huge objects. You would just have to give it a homebrew characteristic to let it morph into other things than treasure hoards.
Yes if it is big enough. There are tales about such things in previous rulesets.
My party found an underdark dwarven tavern that had become infested with mimics - the tables were mimics, the bar was a mimic, etc.
one of the mimics I came across was a largish key (so tiny sized). My Rogue has a particular code of honor though - no killing kids. even monster pups or whatever. We fed the mimic some rations, and were able to use it to unlock the chests in the room. I'm now taking it with me to tame. even went out of my way to buy animal handling to be able to negotiate with it.