I so wish I had recorded it at the time.
I found a shiny graveler in one of the earlier games inside a cave. I got it down to what must have been between 1 and 10 health without a False Swipe, and I managed to throw three Ultra Balls at it. Every single Ultra Ball failed, and the Graveler promptly used Selfdestruct after the third ball.
Saddest day in Pokémon for this guy. But Wait! There's More!
In the same week I had run into a Geodude that was also a shiny. An extremely similar situation occurred with this one, the only differences being that I only got to throw one Ultra Ball, and it had like about a quarter of its health left. This one also exploded forever.