For the past two weeks, every time I hop onto Twitch, I’ve found myself browsing through Pokémon FireRed and LeafGreen streams so I can watch people play the classic games in perhaps the most difficult ways possible.

If you’ve played through a mainline Pokémon title before, you’ve probably been able to get through the game without too much trouble. I’m pretty sure all of my friends growing up experienced some variation of just letting their starter carry them to becoming the Pokémon champion. But there’s a community of players making the games dramatically more challenging by applying some form of what the community calls “IronMon” rulesets.

The gist of IronMon is that it’s a really hard randomizer. The pokémon you encounter, their moves, and the items you pick up are randomized, while the pokémon you fight in the wild or those owned by trainers have increased levels. Yes, this means that your starter pokémon will be random, too, so you won’t just pick between Bulbasaur, Charmander, and Squirtle. According to the rules, you even can’t peek at which pokémon are available to make your choice; you just have to walk up to a pokéball and accept what you get. (Though streamers often check the other pokéballs after they’ve already decided which one they’ll pick to see what they might be missing out on.)

IronMon challenges are kind of like Nuzlocke runs but even harder. The standard IronMon rules, to me, sound like an already mind-boggling level of difficulty — what if my starter is a weak Metapod? But the challenge doesn’t stop there. If your pokémon faints, you must release it or put it back in storage, meaning you can never use it again. And on Twitch, I tend to drift to watching a harder version of the challenge, dubbed Kaizo IronMon, where players must battle with a single pokémon. If that pokémon faints, the run starts all the way over.

If you’re interested in reading all the rules, you can check them out here (and learn about an even harder IronMon ruleset, survival), but I really recommend just popping onto Twitch and checking out some streams.

Many streamers will likely be stuck in Professor Oak’s lab or tromping around the initial parts of the game. It’s quite difficult for a pokémon to be good enough to survive the early areas. Though it might sound boring, I find the early game entertaining — the chat typically helps vote on which starter to pick, for example, and it’s hilarious when the chat picks wrong and the streamer immediately loses. Sometimes, streamers will also “pivot” to a new main pokémon, and they’ll will usually debate the merits of picking one pokémon versus another with their chat.

When a run gets going, it’s thrilling. Every opposing pokémon poses a potential danger, even when the streamer’s pokémon is dozens of levels ahead. An opponent can defeat even the most powerful pokémon with a well-timed countermove or by whittling down health through a status effect, ruining an hours-long run. And players always nickname their pokémon, so I’ll get invested in the fates of creatures with silly names like “STEELEDUP” (a Steelix) and “SMILE” (a Blissey).

But more than anything else, I keep watching out of the hope that I’ll see a run go all the way — and to be there when things almost inevitably fall apart. One night, I was watching streamer Iateyourpie (who is credited on the rules site with creating IronMon) absolutely demolishing a run with a powerful Blissey. In the morning, I checked Iateyourpie’s Twitter feed to see how things ended up. I’ll let you watch what happened for yourself in the final battle of the game:

Heartbreaking. But I’m still tuning in to more streams to try and catch the next great run — or even those that are stuck in Oak’s lab.

Screenshots by Jay Peters / The Verge