Machamp

With STAB Fighting-type haymakers at its disposal, Machamp can look enticing to the average player. Being as fast as Exeggutor ensures it edges out and 2HKOes Chansey with even Low Kick, which many Pokemon simply cannot achieve. Similarly, Machamp has the potential to give Tauros and Snorlax trouble, albeit to a lesser extent due to a deathly fear of paralysis. It's also got some fair physical bulk and a handy resistance to Rock Slide, allowing it to switch into and threaten Rhydon. This boils down to solidifying Machamp as a straightforward attacker that benefits strongly from paralysis support.

Machamp's main problem is that while nearly every team includes the "Big 3" Normal-types — which Machamp can excel against in a flat one-on-one — a Psychic-type usually isn't far behind them. Machamp simply can't deal with Psychic-types, often failing to muster even a 2HKO on most and taking massive damage in return. Ergo, while Machamp hits like a freight train, it offers little defensive utility, which often opens gaping holes in its team. Additionally, Machamp despises paralysis, as what little Speed it has is what ensures it can threaten the Normal-types it wants to go after. When looking for a Pokemon to pummel paralyzed teams, Rhydon is often a better choice, possessing much greater defensive utility, immunity to Thunder Wave, and generally superior STAB moves. Machamp is thus a rare sight in RBY OU and generally isn't recommended.