Reserving Bulky WoW Zard-X
Charizard @ Charizardite X
Ability: Blaze
EVs: 248 HP / 100 Def / 160 Spe
Impish Nature
- Will-O-Wisp
- Dragon Claw
- Roost
- Earthquake/Flare Blitz
So, Zard-X being able to sit against Electric Types is nothing new, thanks to his decent (even uninvested) bulk and defensive typing, resisting their STABs and taking little from HP Ice. Manectric is one of the more troublesome for Zard-X since the Intimidate drops make it easier for things to switch into it even without Volt Switch's aid, but Manectric itself is not breaking through him 1-v-1, even with hazards
252 SpA Mega Manectric Thunderbolt vs. 248 HP / 0 SpD Mega Charizard X: 87-102 (24.2 - 28.4%) -- 94.8% chance to 3HKO after Stealth Rock
252 SpA Mega Manectric Hidden Power Ice vs. 248 HP / 0 SpD Mega Charizard X: 78-92 (21.7 - 25.6%) -- 2.1% chance to 3HKO after Stealth Rock
Thus enters Crawdaunt. This is slightly trickier as Zard-X can't switch into Crawdaunt if hazards are on the field, and even then it needs to be very healthy to switch into a damaging attack. If he comes in on the SD or a Voltturn of his own, Crawdaunt can't beat him in shape to finish the rest of the battle. Even with the SD boost, Crawdaunt has to rely on Crabhammer for the 2HKO after a burn, so Zard-X can burn it, tank the "boosted" Crabhammer, and then Proceed to Roost against it.
+2 252 Atk Life Orb Adaptability burned Crawdaunt Crabhammer vs. 248 HP / 100+ Def Mega Charizard X: 204-240 (56.8 - 66.8%) -- guaranteed 2HKO
+2 252 Atk Life Orb Adaptability burned Crawdaunt Aqua Jet vs. 248 HP / 100+ Def Mega Charizard X: 82-97 (22.8 - 27%) -- 51.2% chance to 4HKO
While Zard-X takes a net loss of health over time, Crawdaunt's health chips away fast between Burn residual and its own LO, crippling it if it fishes for a Crit.
If Crawdaunt tries to "outboost" the burn, it would still need to rely on Crabhammer, as Aqua Jet still doesn't guarantee the 2HKO at +6 after the Burn.
+6 252 Atk Life Orb Adaptability burned Crawdaunt Aqua Jet vs. 248 HP / 100+ Def Mega Charizard X: 162-192 (45.1 - 53.4%) -- 39.5% chance to 2HKO
And if the Zard-X user gets the 2nd Roost to max himself out, Dragon Claw can KO after the 2 turns of burn damage (24%) trying to get those boosts and any amount of LO recoil Crawdaunt would have to deal with.
0 Atk Tough Claws Mega Charizard X Dragon Claw vs. 4 HP / 0 Def Crawdaunt: 160-190 (59.7 - 70.8%) -- guaranteed 2HKO after burn damage
As a small aside, this Zard-X can also lure Landorus-T, another common partner to Manectric for the Intimidate-Voltturn shenanigans.
Yeah I know I'm stretching, but most of the better OU answers were done by the time I got here.