N asks:

Who would win between a billion Pokémon and all lions? My moneys on the lions.

…I- you…

…it-

…hmm

Is… is this an accidental reversal of the “billion lions vs. all the Pokémon” meme that’s been going round, or an intentional one?

‘cause, as stated, that’s an extremely bad bet; those lions are, like, super dead.

How many lions are there in the world, anyway?  Like, less than 100,000, right?

go go gadget Wikipedia

so, like, obviously no one knows exactly how many, but 20 or 30 thousand seems like an estimate of the global population of wild lions that experts agree is reasonable.  If there’s just as many in captivity (which, like, there probably aren’t, but the number is at least in the thousands, so let’s be generous to the lions here) then “all the lions” amounts to maybe 50 or 60 thousand.

Assuming we’re using a standard billion (a thousand million, 10⁹) rather than an old-school British “billion” (a million million, 10¹²), each lion is going to have to fight off at least 16,000 Pokémon.  And, like… if nothing else, they would get tired.  Even if all the Pokémon are something cute and helpless like, I don’t know, Igglybuff, and each lion is killing one every ten seconds or so, and the Pokémon politely line up to be fought one at a time, that still works out to 46 hours and 17 minutes – i.e. almost two days, without rest or sleep.  Lions are not good with endurance (certainly much worse than humans); they can go on fighting at full capacity for maybe a couple of minutes at a time, and are normally active for only 4 hours each day.  Meanwhile, there’s so many Pokémon that they don’t need to be fighting all at once to overwhelm the lions; at any given moment, it’s possible for the vast majority of them to be resting, so if the lions ever try to take a break, they’ll be overrun instantly.  They’ll drop dead of exhaustion and stress before they even make a dent.  Maybe you have a billion Magikarp, and they’re so harmless that the lions are free to take breaks and fish the Magikarp out of a pool or river at their leisure, but even then the lions probably die of malnutrition because Magikarp are such a hopelessly rubbish food source.  Besides, when you have a billion Magikarp, some of them are bound to evolve sooner or later.  And these are the best case scenarios for the lions, with some very generous and unrealistic assumptions in their favour; if some of those billion Pokémon are actually dangerous, or even take some slight amount of effort to kill, then G fµ¢£in’ G. We could be even more generous and use estimates for the much higher population of lions at the beginning of the 20th century (200,000 gets thrown around a lot as a total for Africa, and there would have still been significant populations throughout the Middle East too, so let’s guess 250,000 total), but even then, we’re looking at a solid 11ish hours just to kill Pokémon that are lining up and letting themselves be killed. If they fight back in any way, I can’t see the lions having any hope of winning.

I probably should also address the standard form of this question too – all the Pokémon (presumably one of each; let’s assume that, counting generation VIII, we’ll have about 920) vs. a billion lions.  And… well, for much the same reasons, I think I have to go with the lions.  There’s a lot you can do, tactically speaking, with one of every Pokémon (manipulate terrain to create choke points, set up spikes and barriers, bombard the lions from the air, etc.), and a few of them are just ludicrous and could take on dozens, maybe hundreds of lions at once, but the numbers disparity is even worse than in the previous case (meaning that this time, the lions’ poor endurance isn’t going to come into play – every time one of them drops, it’s replaced by one that’s fresh and rested).  Each Pokémon is responsible for taking out almost one million and eighty-seven thousand lions. One million is about the total number of casualties for both sides at the Battle of the Somme, which went on for over four months.  And, well, there are a lot of Pokémon that would lose to a single lion, and many more that would struggle against two or three lions working together, so the strongest Pokémon are realistically going to have to take charge of several million apiece, fighting them a hundred or so at a time.  You might do fine against the first ten thousand, but even if you can keep fighting that long (and remember, the Pokémon games do have a mechanic for quantifying exhaustion – PP, which runs out long before the one millionth enemy), you’re eventually going to be crushed to death when the enormous pile of dead lions falls over.  Even Flying Pokémon with ranged attacks can’t stay in the air forever.  And yeah, there are responses to this like “well, Rayquaza (or whoever) can just go to space and ignore them,” which is true but I’d argue that’s not really “winning the fight”?  That’s more like forfeiting.  Like, Dialga and Celebi could also just blink a hundred years into the future and declare victory because the lions have all died of old age, but I’d suggest that this wouldn’t really be in the spirit of the question.  You sort of need to define boundaries and victory conditions more specifically in order to get a real answer – some kind of objective point that one side is defending, for instance.