The obvious is Endgame when Iron Man had the stones.
The next is The Last Dragon, when Leeroy had the Golden Glow.
I feel like it’s a trope of the 1980s on, but I can’t remember additional examples.
And I definitely don’t remember the earlier examples.
What shows had that oh so satisfying “oh really? Do you now?” Twist at the end of the story.
Stargate SG1 where humanity gets the Asgardians knowledge.
Shang Chi gets the 10 rings.
Luke learns to use the Force and blows up the Death Star.
Aang masters the elements, Avatar state, and energy bending.
I’m 1 for 4 on these. Will look into if I can view the 3.