Conjure Mimic

When you cast this spell, you touch a medium nonmagical object and transform it into a mimic. If the object contains items, such as a barrel of food, they remain in the mimic until the spell ends or it drops to 0 hit points. The mimic remains motionless until it is triggered or if it must defend itself from a hostile creature. 

You decide what triggers the mimic when you cast the spell. The most common triggers are using or opening the object or approaching within a certain distance of it. You can further refine the trigger so the mimic is only activated under certain circumstances or according to a creature's physical characteristics (such as height or weight), or physical kind (for example, to only attack hags or constructs). You can also specify creatures that don't trigger the mimic, such as allies or those who speak a certain password. 

The mimic dies and reverts to its nonmagical object form when it drops to 0 hit points. The mimic is friendly toward you and your companions. In combat, roll initiative for the mimic, which has its own turns. The mimic obeys any verbal commands that you issue it (no action required by you). If you don't issue any commands to it, the mimic remains in object form or defends itself from hostile creatures, but otherwise takes no actions. When a mimic created in this way uses its shapechanger feature, it can only polymorph into the original object or back into its true, amorphous form. The GM has the mimic's statistics.

At Higher Levels. When you cast this spell using a spell slot of 5th level or higher, you can transform one additional nonmagical object into a mimic for every two levels above 3rd. The objects must be within 30 feet of each other when you target them. In combat, the mimics roll initiative as a group. You may choose different triggers for each mimic.