1. When you dive into the core of a nuclear reactor because it seemed like a good idea at the time and emerge as the newly undead champion of people who do really stupid shit for no discernable reason.
2. When you accidentally steal a megalorry full of plastic skeletons instead of that other megalorry full of fine art that you were planning on stealing and whilst you are hanging out with the skeletons in hiding you end up making them into a giant automated plastic bonespider and using it to navigate the sewers where it scares off various of the city’s supervillians, leading to your coronation in the local media as some kind of mystery urban bonespider benefactor.
3. When you travel so far into the depths of the internet that you emerge out the other side, blinking and slightly shit-smeared, into a shining land of future mysteries where you are transformed into pure and delicate data, routed seven times around the world, and remade into a superhuman with near-unimaginable powers apart from when the wifi is down.
4. When you have so many cats that eventually they forget that you are not a cat and initiate you into the secret midnight rituals of cats which involve fusing together into a giant furry catsuit twelve metres tall and rampaging about the city kicking bins over and you vow to use that knowledge to fight refuse-related misdeeds in your neighborhood like putting the wrong stuff in the recycling and so on.
5. When the dark speaks to you and you speak back to the dark and eventually you get to know it and it’s actually kind of nice and sometimes it will let you ride on its back through the glowing cities of the world and you can ask it to stop so you can hop off and right any injustices that you happen to see in passing and sometimes the dark will even punch people for you, it’s not fussy about that kind of thing.
6. When there is a dramatic global decline in imagination due to some kind of carbohydrate-borne virus making it quite easy to become more powerful than any given person can possibly imagine, so superheroes are ten a penny and they all have origin stories where they tripped over a doorstep and became more powerful than you could possibly imagine, or sneezed unusually hard and became more powerful than you could possibly imagine, or suchlike.
I really like #5