>>34142122Brock's Onix in RBY, if you didn't pick Squirtle. If I'm not mistaken, Bulbasaur didn't get Vine Whip at a level you were likely to reach before Brock unless you consciously ground for it. To a lesser extent in FRLG, since Onix was surprisingly fast and could KO Charmander before Metal Claw did its work, and Rock Tomb meant it actually had an attack worth using.
Cynthia could really have been, since her team absolutely shitstomps any of the starters, and the cover dragon, so if you were running the game like a proper 8-year old, she was hard.
BW Ghestis' Hydreigon is a beacon of normie memes to this day.
Elesa of Gen 5 might count, since the game tricks you into thinking she will be easy because of the Ground types you can get immediately before.
Gen 3 Brawly was a bit hard if you were playing Ruby, and couldn't fuck his shit up with Sableye, and didn't have a well-leveled Tailow.
Wattson could be tricky without Marshtomp as well. Flannery could be tough if you only used one Pokemon, since Sunny Day+Overheat could pretty much ruin anything's day.
HGSS Bugsy was surprisingly difficult if you didn't have Cyndaquil, and doubly so if you went hardmode.
