Base Stats
HP: 115
Atk: 140
Def: 130
Spatk: 55
Spdef: 55
Spe: 40
**Disclaimer** This is my first time doing one of these, please feel free to let me know if I've messed this up or not included vital information for this format.
Rhyperior is an interesting choice in OU, thanks to its signature ability Solid Rock (Reckless is completely useless and Lightning Rod is outclassed) it has very high raw physical bulk and poor special bulk via its low special defence stat alike Great Tusk. Pokemon such as Great Tusk, Ting Lu, Gliscor and Landorus T are similar in terms of bulky ground types which can be used with a Stealth Rock Utility/ Phazer set. Rhyperior also didn't receive much from the DLC, notably losing toxic and gaining niche coverage moves such as Temper Flare despite already having Fire Punch and Heat Crash for example. This overall can make Rhyperior's defensive sets more passive as toxic is a big game changer and can improve matchups against bulky Pokemon like Ting-Lu and Dondozo which don't have reliable recovery.
Notable Set, Bulky Stealth Rock
Rhyperior @ Leftovers
Ability: Solid Rock
Tera Type: Water/ Grass/ Fairy/ Steel
EVs: 252 HP / 252 Def / 4 SpD
Impish Nature
- Stealth Rock
- Earthquake
- Rock Blast/ Stone Edge
- Dragon Tail/ Roar/ Ice Punch/ Protect
This set utilises Rhyperior's stats to the fullest. Thanks to its massive bulk and solid rock, it can pivot into physical threats including:
Dragon Dance Dragonite
252+ Atk Dragonite Earthquake vs. 252 HP / 252+ Def Solid Rock Rhyperior: 109-130 (25.1 - 29.9%) -- 0.1% chance to 4HKO after Leftovers recovery
+1 252+ Atk Dragonite Earthquake vs. 252 HP / 252+ Def Solid Rock Rhyperior: 165-195 (38 - 44.9%) -- guaranteed 3HKO after Leftovers recovery
Rhyperior can win 1v1 with rock blast, with dragonite being the main reason to run rock blast over stone edge due to multiscale pre tera, or dragon tail if dragonite is likely to tera assuming it isn't the last mon on the field.
Gouging Fire (Life Orb Entei will stand in for now to mimic protosynthesis boost and +1 attack from dragon dance in the sun and Rhydon to imitate gouging fire's bulk)
+1 252 Atk Life Orb Entei Flare Blitz vs. 252 HP / 252+ Def Rhyperior in Sun: 159-187 (36.6 - 43%) -- 97.8% chance to 3HKO after Leftovers recovery
+1 252 Atk Life Orb Tera Dragon Entei Outrage vs. 252 HP / 252+ Def Rhyperior: 211-250 (48.6 - 57.6%) -- 47.7% chance to 2HKO after Leftovers recovery (meaning gouging fire would have to already be +1 when rhyperior switches in)
0 Atk Rhyperior Earthquake vs. 0 HP / 8 Def Tera Fire Rhydon: 246-290 (70 - 82.6%) -- guaranteed 2HKO
0 Atk Rhyperior Rock Blast (3 hits) vs. 0 HP / 8 Def Tera Fire Rhydon: 186-222 (52.9 - 63.2%) -- approx. 2HKO
This means Rhyperior can effectively check Gouging Fire without tera involved, and Tera water or Fairy Rhyperior can stop Gouging fire if it tera's into one of its respective STABS in theory.
And
Iron Boulder (Ogerpon Cornerstone Stand-in due to same atk stat, and Dewgong due to same bulk and Dewgong will be tera rock)
0 Atk Rhyperior Earthquake vs. 0 HP / 0 Def Tera Rock Dewgong: 348-410 (108.4 - 127.7%) -- guaranteed OHKO
252 Atk Cornerstone Mask Ogerpon-Cornerstone Earthquake vs. 252 HP / 252+ Def Solid Rock Rhyperior: 111-132 (25.5 - 30.4%) -- 0.7% chance to 4HKO after Leftovers recovery
252 Atk Cornerstone Mask Ogerpon-Cornerstone Close Combat vs. 252 HP / 252+ Def Solid Rock Rhyperior: 135-159 (31.1 - 36.6%) -- guaranteed 4HKO after Leftovers recovery
This means any unboosted hit from Boulder Shoulders will effectively bounce off of Rhyperior due to its huge bulk.
However this set is flawed, Rhyperiors innate typing leaves a lot to be desired and can be a momentum sink for defensive pokes like Alomomola and Great Tusk to get momentum due to rhyperior's natural weaknesses causing it to lose 1v1 and physical attackers such as Ogerpon Wellspring, who can OHKO Rhyperior with ease.
Rhyperior may also have a niche as a bulky choice band wallbreaker similar to Great Tusk in pre-home OU, however due to its low speed and exploitable typing it leaves a lot to be desired as well as its prediction reliant nature due to such a rock resistant OU. However with good prediction this is a decent anti meta choice for a set and a pokemon overall. Rhyperiors flaws include: poor special bulk, overall bad defensive typing, no reliable recovery, 4MSS and a weakness to status from Pokes such as toxic Gligar unless running an ice punch variant which compromises on longevity or utility from dragon tail or protect respectively.
Conclusion
While Rhyperior is still my GOAT, with some decent traits at that, these traits can be replicated with other less flawed pokemon. As a result Rhyperior is niche pick at best and mostly not really worth your time. However, with the right team composition he can put in the work considering he has some ok match-ups worth looking into at a baseline and appreciates at least being able to tera out of his mediocre innate typing to help in some matchups.
has Solid Rock and so does the not-in-gen-9 
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