Are adventurers like black widows or blue-ringed octopi to dragons?

Valid post, and given the scale of DnD dragons I'd say that an adventurer is about the size of a cat relative to an adult dragon. IRL, a cat being able to attack you and successfully kill you would be pretty fucked up even if it's theoretically possible.
Incidentally however...
A cat in DnD does have the ability to reliably fight and kill a Commoner.
So what I'm saying is that it should actually be a valid plot to put humans in the position of some shitty media's dragons- once dominant, but through the power of one especially heroic housecat who has exceptionally strong plot armour, we are reduced to a dying race, ancient and forgotten by the new era.
- More like a pride of lions bringing down an elephant, or maybe wolves on a bison.
  1v1 dragon slaying would still be more like a badger taking on a tiger.
  Player characters (as opposed to non d&d dragon slaying stories) aren't usually as ill prepared as a cat is vs a human, and rarely "hunt" alone. PCs have better weapons than claws and teeth, and the ability to coordinate attacks reduces the advantage of size and power the dragon has more than the comparison between a cat and a standard, unarmed human.
  I do, however, love the idea presented :)
  
  In a fight badger vs tiger I'm not sure if I'd put my money on the tiger. At least the European badgers are nasty af. Golden rule: if you hit them / run them over with a car, don't leave the car. They're pretty sure still alive and mad as hell and you'll regret it.
  
  To use another IRL example, humans did drive the wooly mammoth to complete extinction with little more than sharpened rocks attached to sticks.
  Humanity's ability of cooperation is a massive force multiplier and let's us accomplish tasks that would kill and individual.
- Source? A Commoner has 1d8 hp compared to a cat's 1d4. A cat's AC is 2 higher, but a Commoner's attack modifier is 2 higher. If the Commoner has a club, they're dealing 1d8 damage instead of 1d4, but even without that it's the same damage. A cat can absolutely win if it gets lucky. After all, one in eight commoners have only one hitpoint, but reliably?
  Also, I don't think the fight's really comparable, since at low levels randomness matters a lot more. A Commoner is equally likely to have 1 hitpoint as 8. An adult red dragon is 95% likely to have HP from 227 to 286. And likewise, when you're dealing damage, it would be a lot more consistent.
  That said, while a cat can't reliably kill a commoner, a party of four cats definitely can, and going up against a large number of weak enemies is not good in general. Also, dragons just get a few abilities, and depending on the DM maybe a few spells that aren't that high level. Going up against human spellcasters is not a great idea.

wait, does this mean that dragons think about dragon/human romances the same way we think about bee movie????????
i.... i need a minute,
- According to all known laws of aviation, there is no way a human should be able to fly.
  
  The human, of course, flies anyway, because it does not care what dragons think is impossible.
- What about donkeys?
  
  Life uh finds a way

Mortality is a birth defect...
Vainqeur, Best Dragon

Turned into a dragon and still got her ass handed to her. Awkward!

@MouseKeyboard someone in the thread likened humans to dragons as being like cats. This has so much potential. Like a dragon that pampers their disgruntled pet human. Who gets angry and knocks over priceless treasure when it doesn’t like what it gets for dinner. One dragon hordes a whole community of humans. One dragon has a human that kills goblins and leaves them for the dragon because it’s pretty sure the dragon doesn’t know how to feed itself.
- That last line is peak human energy. Aww the widdle kitty hasn't killed anything all week!
  Leaves a deer carcass for their favorite tiger
  
  @Maggoty we didn’t domesticate cats.
  They domesticated us.

Would there be dragon's that fear humans in the same way arachnophobe's fear spiders?