Why not make enemies with separate, individually destroyable parts?

One I thought of is some kind of gremlin car, which would have a turret on top. It would shoot at you and try to run into you to attack.

It would have 4 destroyable wheels - When you destroy any of them, a Mender would come out and start trying to repair them. You can attack the Mender while he's repairing them. The turret would continue shooting at you when a wheel is destroyed, but the car can't chase you until the Mender repairs the wheel. (The mender can heal himself, but can't repair the wheel at the same time.)

If the Mender is killed, the turret would stop working and a Thwacker would come out.

Another option would be to just attack the car itself. The car has a large amount of HP, though. If the car is destroyed, then the mender and thwacker would come out at the same time. All wheels would instantly be destroyed.

It needs a space that has a 1 1/2 tile width to go through, meaning you can destroy one block in a wall of blocks and go through while the car can't follow you.

Both gremlins would drop crowns, heat, materials, and whatever else they usually can drop, and the car itself has a chance to drop materials but nothing else. Wheels drop nothing. If the mender is killed and the Thwacker leaves the car, the car will remain so you can destroy it for the materials.

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This would a somewhat rare enemy. One area it would probably be found in is Deconstruction Zones (usually one in each DZ, though there can be more or none at all).