Articulated ears with a space for a micro servo. I've designed them for a costume for the character Barf, from the movie Spaceballs.

The ears could pass as small bunny ears as well. Each ear has a solid base plate with six holes to attach to a hat, or in my case, to be sewn to a wig. Future iterations may be attached to a flexible headband unless someone beats me to it. ;)

How I made them:
I used the tutorial from Nerys (https://www.youtube.com/watch?v=NmV726FYrBk&t=1804s) for designing the articulated hinges, but used a triangular prism to cut the lines instead of the rectangular prism provided. I used the hinge and punch he created in his Articulated Anything starter Files (https://www.thingiverse.com/thing:2840744). Thanks Nerys!

I tested these at 10mm (too stiff) & 5mm (too flimsy) depths. I found 8mm to be a good medium.