There is a card in Slay the Spire, the excellent roguelike deckbuilding game, called Claw.
Viewers of Slay the Spire content love to parrot that "Claw is the law," which is to say that when Claw comes up, you should take it. The reason is simple: it's a fun card that holds a promise of big numbers.
Unfortunately, it's also not very good. (And that's another part of why people like to see it. It's not used often enough to get boring.)
Upon first play, Claw deals 3 damage to a target. Each time it is played, the damage of all Claw cards in your deck goes up by 2 for the remainder of the fight. So, in theory, it scales infinitely. Claw incentivizes you to pick up a few more Claw cards and play them as many times as possible.
However, the initial damage is quite low, and it takes a good number of uses before Claw becomes a card worth playing compared to other damage options in Slay the Spire. So until you build a deck that quickly and reliably enables you to find your copies of Claw, and allows you to find ways to play them repeatedly, it's more likely to be dead weight.
In Slay the Spire, you typically can't afford to wait until you've put together all the pieces necessary to make a Claw deck work. If your deck isn't strong now, you'll probably die before you get to later. You can rarely afford to put dead weight in your deck.
Upgrade math
Claw can also be upgraded into Claw+, which is why I'm writing this post. In the game, you can visit campfires where you may choose to rest (to regain health points) or upgrade one card in your deck. Claw's upgrade is mild: it raises the base damage from 3 to 5.
Many people find this underwhelming, and think the upgrade would be better if instead, it made Claw scale more dramatically. For example, the card text could say: "Deal 3 damage. Increase the damage of ALL Claw cards by 3 this combat."
But I don't think this is a very good upgrade. The current Claw+, after five uses, will have done 45 damage. Theoretical Claw+ (let's call it Claw++) will also have done 45 damage. So Claw++ would only be better than Claw+ after a minimum of six uses.
In a deck that makes Claw work, you can expect to play Claw far more than just that. In late-game boss fights, you may even play it 30 times or more, at which point Claw++ would obviously deal vastly more damage than Claw+.
However, the whole problem of Claw is that your deck will likely have failed before then. You need substantial card draw and deck manipulation, energy generation, or at the very least sufficient defensive capabilities to stay alive until Claw finally starts doing something worthwhile.
If you manage to play Claw 30 times, great. At that point, even an unupgraded Claw is still doing incredible damage. But Claw++ not only doesn't help you in the early game, where Claw is most likely to be a bad pick, it's actually worse than Claw+ due to needing a bit of extra time to ramp up to overcome the low initial damage.
I also don't think the regular Claw upgrade is as bad as people say. If picking Claw means building a deck that revolves around playing Claw as many times as possible, then surely increasing the base damage of the card isn't that bad. It's only an additive upgrade, but it multiplies with how often you play it. Of course, it effectively only starts you one step ahead on the ramp, which is to say it's equivalent to playing Claw one more time. So if you have other upgrade options that help you play Claw more often, they're going to be better.
Conclusion
So what's the point of all this? Claw is fine the way it is. Part of what makes it fun to use is the difficulty of winning with it. If it were changed to have better scaling, it would just get better at what it already does well: do a lot of damage once played many times. And if its early damage was shored up, then its only real weakness would be eliminated and Claw would likely be overpowered. Then Claw would really be the law, and that would be no fun at all.