Golem

Golem's Rock / Ground typing makes it a strong attacker that crucially hard counters Zapdos and Jolteon while resisting Normal-type attacks. Its QuakeSlide coverage is completely unresisted and able to 2HKO Pokemon like Rhydon, Zapdos, and Alakazam. This makes Golem excellent at bullying paralyzed Pokemon, but what tops this all off is Explosion. Golem's Explosion, while just shy of Snorlax's Self-Destruct's strength, is terrifyingly strong, even having a chance to OHKO Starmie. Explosion Golem is likely to break even (at worst) against most Pokemon, and this has kept it relevant for decades.

However, Golem is very slow and has devastating weaknesses to most common special attacks; it has to run from Blizzard, Surf, Razor Leaf, and whatnot. Even neutral special attacks such as Psychic will deal significant damage to Golem. Further, being so slow means Golem gets forced to use Explosion in many one-on-one fights. Due to these two setbacks, Golem is very reliant on enemy teams being riddled with paralysis before it gets going. Plus, while Explosion can theoretically compensate for Golem's Speed and let it break even frequently, Golem generally shouldn't use Explosion until the opponent's Zapdos or Jolteon is accounted for, lest its team crumble to them. Therefore, decision-making with Explosion is difficult until Zapdos or Jolteon is paralyzed or KOed, after which it can be deployed more freely and actually exert offensive pressure. This can make its role seem a little paradoxical to the uninitiated.

Golem famously fell from RBY OU in 2019, ending a long-standing battle between it and Rhydon for places on competitive teams. Understanding this is important, as while many teams can use Golem adequately, they tend to be better off with Rhydon instead. This is because Rhydon has a higher Attack stat, which allows it to achieve damage thresholds like 2HKOing Chansey and rarely 2HKOing Starmie. It's also capable of sometimes 3HKOing Slowbro, defusing a key threat if it switches in on Rest. The extra damage output against Exeggutor, Rhydon's and Golem's biggest counter and most common switch-in, is also a key advantage; Exeggutor cannot safely switch in as much as it would like against the rocky rhino. Additionally, Rhydon is bulkier thanks to its higher HP, which also enables 104 HP Substitutes to stomach Seismic Toss or Night Shade. This quirk helps Rhydon reliably run and use Substitute in general; it can fish for Substitute in situations where Golem is forced to use Explosion, making it even harder for Golem to justify itself on teams. Regardless, Golem's strong perks over Rhydon remain recognized: possessing the second-strongest self-KO move and outrunning Rhydon allow it to indisputably succeed over Rhydon on highly specific teams.