This neatly holds a LARGE Chuckit ball flinger and ball.

It mounts on the wall (or in my case, the inside of a cupboard) with three screws.

I added our dog's name in Bambu Studio, but I've left the model blank for you to customise (or not) as you wish.

I printed this with all the default settings. It needs no supports or adhesion settings. It seems pretty sturdy with two walls and 15% infill, but I'll see how this holds up over time, and may reprint with another wall or two if it breaks.