Rampaging across the African savannah and intimidating a lion into serving as a mount, then publicly smacking down and humiliating a young Flintheart Glomgold, who had just left him to die in the savanna. (The Terror of the Transvaal)
Cowing Wyatt Earp by simply taking out his Number One Dime and swinging it around.
Bringing down an entire steamboat around Soapy Slick, with his bare hands, after Soapy makes fun of the death of Scrooge's mother.
You really need to read that to fully comprehend just how badass Scrooge is.
His discovery of the Goose Egg Nugget:
"Great honk, this rock is heavy! How could it weigh so much unless... unless it's gold! Gotta rinse off the mud! A nugget this big would make me the richest man in the Klondike! But if it is gold, that wil mean my quest is finished! I'll be rich! I'll never be the same again! Will clean air smell any sweeter? Will sunny days be any brighter? Will starry nights hold any more wonder or will I lose all that? Do I really want to be... rich?" (ponders; gets a glim of gold in eyes) "YES!!!" (washes rock) "It's GOLD! SOLID GOLD! As big as a goose egg! Ha ha ha ha ha... I'm RICH! RICH! RICH!"
...and the "The End" message is replaced with "The Beginning."
Related to The King of the Klondike, there is.
Going back to rescue the bad guy's sled dogs (but not the bad guys themselves) from an ice floe about to go over a waterfall. (The Prisoner Of White Agony Creek)
Roy Bean: Based on careful deliberation (and many years of experience with life), it is the verdict of this court that what's going on in that cabin is not a hangin' offense in Langtry, Texas — or anywhere else. Thank gosh!
Not to mention almost negotiating perpetual rights to the Airplane and The Movie Camera in exchange for keeping his mouth shut about the archaeological treasures he's found.
Taking out a group of Beagle Boys fifty years his junior in The Richest Duck In The World.
From that same chapter, showing a very skeptical Donald his ginormous money bin.
Scrooge gets one by collapsing Fort Duckburg on Teddy Roosevelt in (and then preparing to fight him with a piece of wood the size of a telegraph pole) (The Invader of Fort Duckburg)
"It'll be a dark day when I give in to a mere superpower."
When Goldie first encounters the frozen mammoth that serves as the guardian to Scrooge's mine, she does not faint like he expected but whips out a derringer and shoots it... which Scrooge quickly realizes she could have done to him any moment before that. (The Prisoner of White Agony Creek)
Hortense McDuck defending Castle McDuck from the Whiskerville, complete with Casual Danger Dialogue... (''The New Laird of Castle McDuck")
... topped, of course, by scaring away the United States Cavalry with a broom. (The Invader of Fort Duckburg)
Howard Rockerduck working his tail off to help Scrooge register his copper claim, knowing all the while that it will cause his own mine to be shut down in Raider of the Copper Hill, because he hopes it will teach his own son a lesson.
Also, he taught Scrooge how to be a prospector for two cents. This makes him indirectly responsible for Scrooge becoming rich.
Every deceased member of the McDuck clan, popping out to frighten away the Whiskervilles in The New Laird of Castle McDuck.
Huey, Dewey and Louie deducing that Scrooge has has owned the map to the Last Dutchmen mine for years and had never realized it. (The Vigilante of Pizen Bluff)
When Scrooge's Uncle Pothole makes the mistake of talking down to Annie Oakley, her response is to blow the bowl of his corncob pipe off with a rifle blast (The Vigilante of Pizen Bluff):
Pothole I... I think I riled her!
Buffalo Bill Nah! When she really gets mad, she'll aim for the other end of your pipe!
Don Rosa's most awesome act was resisting the urge to ignore the infamous robber baron Noodle Incident and not only working it into the story but depicting it and what it does to Scrooge so well.
When Scrooge gets knocked out while making a deal, Matilda and Hortense get a crowning moment by deciding to teach him a lesson, by making the deal in exchange for Roosevelt's stuffed bear (The Sharpie of the Culebra Cut)...
... And then Huey Dewey and Louie get a moment forty years later, by pointing out something that Scrooge missed: that he is the owner of The Very First Teddy Bear, as important (and expensive) an artifact as any of his other finds.
Most of Scrooge's awesomeness is based in how he has found more priceless treasures than perhaps any other fictional character: The Sampo, The Land of Xanadu (during his attempt to find the Crown of the Crusader Kings), The Treasure of the Knights Templar, The First Minted coin of Croesus, The Candy-Egg Ruby, The Crown of Genghis Khan, The Philosopher's Stone, The Golden Fleece of Jason, The Fountain of Youth, The Lost Dutchman Mines, and (according to Word of God) his final discovery, The Trojan Horse. Certainly his record is mixed in actually hanging on to the treasures, but that's mainly a result of Scrooge wanting to play fair, which is kind of awesome in itself.
Don Rosa starts off Scrooge's awesome with his victory at the ending of Son of the Sun.
Scrooge beating up and tossing◊ a Beagle Boy from his friggin' dream unconsciousness so he can talk to Goldie, at the end of The Dream Of A Lifetime.
It get's better: Moments before said Beagle Boy threatens Scrooge, only for Donald to proudly proclaim that this isn't the Scrooge he knows: He's 30 years younger and the rough and tough protecter of the Klondike. Cue Asskicking.
In The Last Lord of El Dorado, Scrooge and his nephews are on a quest for the titular city of gold, with Flintheart Glomgold following them in a variety of incredibly obvious disguises. Near the end of the story, Scrooge confronts Glomgold and not only reveals that he saw through all of his guises, but also takes the opportunity to rub Glomgold's face in some of his past defeats. Finally, after Glomgold himself discovers the treasure of El Dorado, he "tricks" Scrooge into selling him the bank in which the gold is deposited for a bargain price... which is when Scrooge points out that where Glomgold might own the bank, the gold itself is the property of the owner of the land-which happens to be Scrooge. And as the bank owner, Glomgold owes Scrooge major interest on his deposit-to the tune of all the money in the world. Scrooge never gets this, but he determines that the look on Glomgold's face made the whole thing worth it.
Scrooge's most awesome moment of brilliance has got to be the end of Carl Barks' last story "Horsing Around With History." When Donald and the boys deduce that the Beagle Boys are inside the Trojan Horse, they rush into Scrooge's bin to warn him... only to find that Scrooge was Genre Savvy enough to figure out something was up even before they did with all their clues and already has the Beagle Boys captured!
In the Carl Barks one-shot Somethin' Fishy Here (later remade as Something Fishy), a prank from Donald has him believe fish will now be used as money and all his cash is now worthless. As soon as he's recovered from the shock, uncle Scrooge rebuilds a fortune in fish all by himself, in a single day.
Goldie O'Gilt giving Scrooge "A Little Something Special" in the story of the same name.
Gyro's Little Helper robot using Merlin's power to pull Arthur's sword from the stone in The Once And Future Duck.
That's Stonehenge's power. Merlin is a rather lousy bard with no magic power, but a fair bit of wit in this story.
The climax of The Maginificent Seven (Minus Four) Caballeros gives at least one to each of the titular Three Caballeros: First, Donald, after being put down by Scrooge, Gladstone, and Daisy earlier in the story, finally snaps when the villain of the comic (a native chief turned greedy by civilization) escapes in a canoe, leaving Donald, Jose and Panchito in the lost city of Ophir, with no way to get out (due to the piranha-infested river and the city's location on a high plateau). Donald then grabs a vine, swings into the chief's canoe, and proceeds to give him what for. During the scuffle, Panchito and Jose decide to help their friend. Just then, they notice a gigantic anaconda (which had previously attempted to eat Donald) swimming toward the canoe. Panchito ties the snake's tail to a nearby bridge, while Jose subdues it with only his umbrella. Finally, after the chief falls off an Inevitable Waterfall, Panchito ties up the Anaconda by its neck and he and the other Cabelleros ride out of the ruins on it like a bucking bronco.
GladstoneGander of all people, gets one at the end of "A Little Something Special." Blackheart Beagle is making his escape on a hover-scooter, when Gladstone shouts for the mayor to put a reward on Blackheart's capture. The mayor does, and a gust of wind suddenly causes Blackheart's scooter to become tangled in a banner, which results in Blackheart being deposited unconcious at Gladstone's feet. This marks one of the only times Gladstone has used his luck to help others-and he doesn't even seem to be concerned about collecting the reward.
Another Moment of Awesome for Gladstone is his rescue of Donald in "Donald's Lucky Day". Donald falls into a river and is about to drown. Gladstone, instead of relying on luck, or even just letting Donald flail around, instantly rips of his coat and throws himself into the strong current, carries Donald to shore, and gives him the needed help afterwards.
The Italian four-parter story Zio Paperone e l'Ultima Avventura (Uncle Scrooge and the Last Adventure) in its entirety. The premise? Rockerduck, the Beagle Boys, Magica De Spell and Freakin' Flintheart Glomgold do a Villain Team-Up and defeat Scrooge. Magica and the BB exchange targets, so the former makes Scrooge's money vanish, while the latter easily steal the Number One Dime; after such a massive defeat Scrooge's quotations plummet, which allows Flintheart and Rockerduck to buy his entire economical empire. And then they act as benevolent tycoons to gather the masses' sympathies while planning to erase the Money Bin and the entire Killmotor Hill, building a super-technological waste disposal center in their place, just to erase the memory of Scrooges from the hearts of Duckburg's inhabitants. DAMN.
After recovering his spirit Scrooge steamrolls them back: he gains the help of both both Magica, who lost her powers (since Scrooge was bankrupted he wasn't anymore the richest person on the planet, so her plan for richness failed... again... and she was stripped of her powers as a result), and the Beagle Boys, who, since they couldn't get their money (due to Magica losing her powers, thus being unable to making them reappear), pressured the two billionaires only to get backstabbed by Flintheart. Later, with the help of the entire Duck family, he manages to expose Flintheart's "waste disposal facilities" (throwing trash into the bowels of the Earth), takes advantage of both Rockerduck's guilt over Scrooge's (faked) death and fear of Flintheart, and Flintheart's Chronic Backstabbing Disorder to take back Killmotor Hill, and blackmail them both into selling him back his economic empire. For one single dollar. Best. Story. Ever!
Magica de Spell throwing Scrooge into a panic by sending him a threatening Valentine! Top points for style, dahling.
It was the early Carl Barks story Ten-Cent Valentine, for the curious.
Flintheart Glomgold discovering "The Eye of Manco Capac" in The Son of the Sun before Scrooge, then pointing out that even though Scrooge may have claimed the rights to the gold in the area, there's absolutely no gold in his far more valuable find. (Don't worry, of course he doesn't get to keep it.)
Arpin Lusène is generally made of awesome, but the fact that he goes for Adaptive Ability by going back and fixing the universal solvent armor of the flaw that defeated it the first time, then terrorizes Scrooge's "Mooney Been" far more effectively.
In one comic where Donald buys a bit of land, it turns out to be one him and Rockerduck has been fighting over(they have a comparison about who owns more land- the winner will be allowed to use the other's land for a season), despite the lot being rather worthless. John D. Rockerduck shows up mere seconds before Scrooge is about to buy a piece of land from Donald for a single dollar. Rockerduck proceeds to offer Donald a big check. Donald is ecstatic, and Rockerduck doesn't even gloat, just drives home.