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I wouldn't try to attack Skarmory because it's just going to KS you and if you boost again it will Whirlwind you out. Skarmory needs to be trapped and removed first.
Shift Gear is very vulnerable to Sableye though good prediction on Parting Shot means your stats won't drop due to Clear Body.
Running 252 HP means you're still outsped by Choice Scarf Keldeo even after Shift Gear. You have to run max Speed to reach 524 (vs max Speed Scarf Keldeo 519).
Besides Sableye and Skarmory, it's checked by Gyarados/Mega even without the Intimidate drop & Slowbro/King w/o Thunder Punch, Quagsire, and really just about any Steel-type not weak to EQ like Forretress, Ferrothorn, and even Scizor who can wear it down with Pin Missile.
I think Metagross won't be very good until it gets its Mega with Tough Claws which will give it a strong priority Bullet Punch and powerful Gear Grind, making it viable competition to Scizor. Scizor isn't weak to Ground, but Metagross isn't 4x weak to Fire. For now Metagross is probably better suited running some kind of weird King Shield set.
I wouldn't try to attack Skarmory because it's just going to KS you and if you boost again it will Whirlwind you out. Skarmory needs to be trapped and removed first.
Shift Gear is very vulnerable to Sableye though good prediction on Parting Shot means your stats won't drop due to Clear Body.
Running 252 HP means you're still outsped by Choice Scarf Keldeo even after Shift Gear. You have to run max Speed to reach 524 (vs max Speed Scarf Keldeo 519).
Besides Sableye and Skarmory, it's checked by Gyarados/Mega even without the Intimidate drop & Slowbro/King w/o Thunder Punch, Quagsire, and really just about any Steel-type not weak to EQ like Forretress, Ferrothorn, and even Scizor who can wear it down with Pin Missile.
I think Metagross won't be very good until it gets its Mega with Tough Claws which will give it a strong priority Bullet Punch and powerful Gear Grind, making it viable competition to Scizor. Scizor isn't weak to Ground, but Metagross isn't 4x weak to Fire. For now Metagross is probably better suited running some kind of weird King Shield set.
Ever since gen 6 came out I have run most metagross sets with agility and weakness policy. Yeah you will be slower to a scarf but you can still dent a lot of things if not OHKO. With shift gear being superior to agility, it could possibly outboost shell smash in one turn. I run 252 hp and 252 attack adamant cause it can tank a super effective hit with that spread most of the time.
It can be difficult enough to deal with one Huge Power priority user, let alone two of them. Diggersby does a great job of weakening the opposing team so that Azumarill can sweep and vice versa.
Magnezone complements the duo nicely by trapping and eliminating problematic Steel types such as Skarmory and Ferrothorn.
This defensive core does a good job of handling a lot of the biggest physical threats in the metagame (including Diggersby, Terrakion, most Mega Tyranitars) thanks to Intimidate, King's Shield, Iron Barbs, reliable recovery and nice defensive synergy. Between them a lot of useful support options are available too - Defog, Stealth Rock, Spikes, Thunder Wave, etc.
But that Diggersby is not bad lol? I've used it for a few weeks now and it's just great, I made a post about it somewhere idk where. The Eevee General can vouch for this set as well :o
Diggersby is such a potent Pokemon. Currently ruling atop its throne, I decided to take a different approach. I believe I did make a post about this a while back, I don't really know where it is; however, I'd like to bring it up anyways. Using Diggersby as a lead is such an unexpected move because nobody honestly expects it unless Sash + Shell Smash, but we'll not go into that. Anyways, the basic premise of this set is simple: use Spikes when the opponent doesn't have a Skarmory, set a layer of Spikes then Swords Dance when the opponent does. The great thing about Explosion is that it prevents Defog from removing Spikes, making it an extremely reliable setter. Lovely Kiss is very prediction based but it is best against Skarmory because it goes through King's Shield, otherwise wasting Diggersby because it Explodes and Skarmory gets away free. Very effective set and catches many off guard, it also gets the job done. The Eevee General can vouch for the effectiveness of this set!
Anyways, this is my 3000th post o_o. That's a lot. So, as expected, shoutouts.
Big Mentions:
The Eevee General: TEG :>. You're an amazing dude. Very kind and a great person in general (hue) and I wanted to personally thank you for making OMs a fantastic place :]. You're very fun to talk to and are quite sassy at times, this must come from the fact that you're a girl ;]. Anyways, I'd like to once again thank you for being a great friend and a great person~!
Redew: Redew o_o. You're my mentor in all honesty haha, you've helped me so much with learning HTML, improving as a user, and improving as a person. Our conversations are always so much fun and we've become good friends :]. Here's to many more~!
asterat: asterat n_n! We've become good friends and you're such a fantastic team builder. You asked me to put thought into this shoutout, so I will. You're very funny and you're our room's village idiot, although I do agree with room meanie ;]. Some people do think you're rude and mean, they're right, but it's always in a loving way and you are quite kind although you may not admit it. So, yeah. Keep up the great teambuilding and lovingness <3.
Peef Rimgar: Peef <3. You're my boi and you're a super fantastic person. We probably talk more than I talk to anyone else on this website haha, you're just easy and fun to talk to. You're very helpful with real life stuff and are great to talk to about problems in general. Very great friend :].
fleurdyleurse: fleur c:. You GP wizard you. You're a very funny person and are a GREAT GP member. I especially appreciate your devotion to helping others improve and in contrast to my last statement, your silliness as well. You're very humorful and are just a nice person :]. ((GP check this btw))
Hulavuta: Hula :D. Very fun and nice guy and you're kind of a smelly nerd, in an affectionate way. Hulafruita :]. Anyways, you're a consistently nice guy and even though your Wi-Fi sucks ily anyways <3. This is a really lame shoutout, my apologizes >.>
Muk: I'd like to personally thank you for your kindness, loyalty, and devotion to making the Community Mentoring room on Pokemon Showdown! a much better place and for keeping things running smoothly. I admire you greatly user: %[Driver]Muk.