It was a turbo controller with an symmetrical design and a tiny joystick.
It was black with a red "A" trigger button on front, red "B" and "C" buttons on back, a concave section on the top left that housed a tiny joystick, and I believe blue start, select, and turbo buttons.
I'm certain it was a third-party controller.
This is an MS Paint drawing of what it looked like: https://imgur.com/a/9mcxBpY