Oh geez so many but the one that instantly comes to mind is one particular 28 oz. Blur. ASA.
Yes I said Blur. No I am not kidding. Comparing everything shaved, senior, prototype, Ti, I've been fortunate to swing a lot of hot bats, several which were cheater or novelty that only came out of the bag for HR derbies or giggles. I can name a half dozen at least I liked better than the Ultra.
When Sam was doing his compression and other people made fun of him (just like they said Shrimp17 was crazy for rolling bats) he stumbled on the Blur. When you compressed those to the point of ugly--paint coming off in sections and sharktooths starting--they tested against even worked Ultras favorably. All of us who did the comparison with a stock Ultra II found the Blurs hotter. Every single time. The people making fun of him started doing it.
Anyone who says the Blurs suck, which is pretty much everyone who ever swung one, is wrong. Even when the stock ones had their 75-100 swings of hot in between 1000 swings of turd and catastrophic explosion, those swings were HOT. Take a redlining Wrath or Envy and add 15 feet.
So anyway before this bedtime story gets too long, I compressed a Blur myself, but not to the point Sam did. Still needed a couple hundred swings and then...I'll skip the superlatives and stories of guys with WTP getting into the 350' parking lot. Or the backyards or woods or roads I reached and haven't since. That Blur was simply the hottest bat I have put to ball. I wish I would have known (I just thought my swing had finally come together) as I wasn't playing league or sanctioned tourneys and wasted it in BP and pickup games and graduation parties.
When I returned it they sent me that orange and brownish Crush Composite, which is ironic. That was the worst composite bat I've swung that wasn't a Steele's No Limit or Miken HHD.