
Arghonaut @ Covert Cloak/Leftovers
Ability: Unaware
Tera Type: Dark
EVs: 252 HP / 40 Def or Atk / 216 SpD
Careful Nature
- Spikes
- Circle Throw
- Knock Off
- Recover
Arghonaut is very common in the current metagame, and is an effective
counter to the vast majority of Gholdengo sets. It tanks any attacks from it thanks to it's Water/Fighting typing and very good special bulk and can throw out a somewhat powerful Knock Off to chip it down and removing that pesky item. After taking a Shadow Ball or Make it Rain, it can also use that as an opportunity to setup some Spikes or fish a Circle Throw or Knock Off on whatever pokemon switches in, so it's very good at abusing Gholdengo's presence.
Unaware means that it can actually switch into and beat Nasty Plot Gholdengo (unlike Gastrodon).
Leftovers is very useful, however Covert Cloak is safer to ensure you won't face Special Defense drops which are a particular hazard when the opposing pokemon can recover on your face (even if it's actually for Garganacl).
Terra Dark in case of emergency, mostly don't Terra vs this guy.
You want to maximize your special bulk with the EVs, these simply allow you to reach the rounding threshold from your nature, the rest can be invested wherever you want, usually in Defense but possibly in Special Defense. However, one very specific benefit of investing them in attack is that circle throw gains a high chance to break a sub from the very rare substitute terra fighting Gholdengo with Circle Throw. If it's the even rarer HP invested Terra Flying substitute Gholdengo... You got unlucky. You can still get tricked a Choice Scarf, which is quite annoying but definitely not the end of the game for Arghonaut, especially with some clever plays and predictions.
But overall this still beats a lot of Gholdengo sets that other counters cannot, it's easy to fit on a team, and can take advantage of Gholdengo bringing it in better than other counters, which is why I believe it is one of the best counters available.
0 Atk Arghonaut Knock Off (97.5 BP) vs. 0 HP / 0 Def Gholdengo: 158-188 (50.1 - 59.6%) -- guaranteed 2HKO
0 Atk Arghonaut Knock Off vs. 0 HP / 0 Def Gholdengo: 106-126 (33.6 - 40%) -- guaranteed 3HKO
40 Atk Arghonaut Circle Throw vs. 0 HP / 0 Def Tera Fighting Gholdengo: 76-91 (24.1 - 28.8%) -- 93.8% chance to OHKO (at substitute HP)
252 SpA Gholdengo Shadow Ball vs. 252 HP / 216+ SpD Arghonaut: 99-117 (23.9 - 28.2%) -- 92.1% chance to 4HKO
252 SpA Gholdengo Shadow Ball vs. -1 252 HP / 216+ SpD Arghonaut: 148-175 (35.7 - 42.2%) -- 92.1% chance to 3HKO after Leftovers recovery
252 SpA Gholdengo Make It Rain vs. 252 HP / 216+ SpD Tera Dark Arghonaut: 148-175 (35.7 - 42.2%) -- 92.1% chance to 3HKO after Leftovers recovery
252 SpA Tera Fighting Gholdengo Focus Blast vs. 252 HP / 216+ SpD Arghonaut: 148-175 (35.7 - 42.2%) -- guaranteed 3HKO