What is this object in my car?

It's attached to the inside of the windshield, next to the baseplate of the rearview mirror. I don't remember if it was always there or not but I don't think it's the car's rain sensor as that's on the opposite side of the baseplate, and I know it's not the car's microphone for Bluetooth, as that's in a different spot as well. It's a 2017 Toyota Prius (Four Touring).

The top half of the second picture is the reflection on the windshield, as the picture shows the front of the object (the part that faces outside the car).