The wackiness has a very 90's web feel to it. I could see it fitting into some apps where it's consistent with the overall design language but for a more normal

The wackiness has a very 90's web feel to it. I could see it fitting into some apps where it's consistent with the overall design language but for a more normal app, I would go with a green check. It could maybe fade in, or "grow" either in line thickness, or from one end to the other. If the checkbox had a label, it could fade out. Over about 100ms. For the sound, the sound of a single knock on wood. Or maybe a bell or a rapid glissando.