Ditto is not mandatory in the least. Also, there is no reason to run Iron Head, what does it hit that EQ and Rock Slide doesn't? Swords Dance is critical to breaking things like Corviknight.
Ditto @ Choice Scarf
Ability: Imposter
EVs: 252 HP / 4 Atk / 252 Def
Impish Nature
IVs: 0 Atk
- Transform
This is Ditto. You know what Ditto does. Ditto is mandatory.
Excadrill @ Air Balloon
Ability: Sand Rush
EVs: 252 Atk / 4 SpD / 252 Spe
Jolly Nature
- Iron Head
- Earthquake
- Rock Slide
- Rapid Spin
Anyway, I think I FINALLY may have found a use for Zamazenta-Crowned for non-webs teams. Specifically, it can be useful as a Gyarados switch-in. Regular Zamazenta cannot do this because it's weak to Flying and is less bulky. Gyarados is one of the most prolific sweepers in the tier and theres little defensive options against it, so I think this gives Zamazenta-Crowned some merit.
In general, I would advise saving this thing in the back until a Gyarados tries to set-up on you, as keeping as much HP on Zamazenta is critical to trying to beat back Gyarados. After that, you can use Zamazenta as a general attacker and wallbreaker.
Zamazenta-Crowned @ Rusted Shield
Ability: Dauntless Shield
EVs: 248 HP / 216 Atk / 44 Spe
Adamant Nature
- Behemoth Bash
- Close Combat
- Wild Charge / Thunder Fang
- Howl / Quick Attack / Crunch
156 HP EVs is the bare minimum for Gyarados to not kill you at +2 in Rain..
+2 252 Atk Gyarados Max Geyser vs. +1 156 HP / 0 Def Zamazenta-Crowned in Rain: 298-352 (81.8 - 96.7%) -- guaranteed 2HKO after Stealth Rock
(Max Geyser does more in Rain than Max Quake)
However, I put more EVs into HP to add more cushion since there could be some Spikes or chip damage on Zamazenta already.
Zamazenta is naturally slower than opposing Zacian/Eternatus so there really is not much point in running a ton of Speed EVs. This amount used here is to outspeed neutral natured Dugtrio and Jolly Excadrill outside of Sand.
The main thing is that Gyarados can double its HP by Dynamaxing, which is why I put as much as possible into attack power. Wild Charge has the disadvantage of giving recoil, which makes it worse vs Substitute sets, but it does way more damage to a Dynamax Gyarados.
216+ Atk Zamazenta-Crowned Wild Charge vs. 0 HP / 0 Def (Roughly Dynamax HP) Gyarados: 516-608 (79.2 - 93.3%) -- guaranteed OHKO after Stealth Rock
216+ Atk Zamazenta-Crowned Thunder Fang vs. 0 HP / 0 Def (Roughly Dynamax HP) Gyarados: 372-440 (57.1 - 67.5%) -- guaranteed 2HKO after Stealth Rock
Most Gyarados sets I've seen seem to be the Substitute and Leftovers set, so realistically you'll probably come in on Gyarados Substituting, Dragon Dancing on your Electric Attack, and then Dynamaxing Max Geyser/Max Quake to try to kill you.
+1 252 Atk Gyarados Max Geyser vs. +1 248 HP / 0 Def Zamazenta-Crowned: 150-177 (38.7 - 45.7%) -- 15.6% chance to 2HKO after 1 layer of Spikes
If they run Life Orb you still live if they're +1:
+1 252 Atk Life Orb Gyarados Waterfall vs. +1 248 HP / 0 Def Zamazenta-Crowned in Rain: 292-344 (75.4 - 88.8%) -- 12.5% chance to OHKO after 1 layer of Spikes
(thats assuming Rain which would likely not be up in this scenario)
Overall it's not a perfect answer, but I think it's a pretty decent one. Wild Charge is better IMO since it does enough damage to usually OHKO Gyarados.
You have some decent attacking stats still so you can just smack things around after Gyarados is gone or if the opposing team doesn't have one. Last slot is pretty filler, Howl is for the attacking boost, Quick Attack since priority is generally good, Crunch to discourage Gothitelle. Since you have good Defensive stats in general you can also use Zamazenta as an emergency check to random stuff like Zacian. Don't try to think of Zamazenta-Crowned as some supposed-to-be wall and therefore bad, just think of it as a bulky offensive attacker that can be critical to not getting your team swept, keeping it's HP as high as possible like Groudon in the last gens since he can be susceptible to chip damage.