Fire / Fairy-typing and Flamethrower
Hmm... Okay, I like this type combination. Remove that Steel weaknes, gain more protection from Bug, Grass, Fairy, Ice and Fire, immunity from Burn status...
But one thing is wrong with this set: Pokemon.
Sylveon shouldn't be Fire/Fairy, just didn't fit on this pokemon. What one guy say - only one fire move what this pokemon can use expect Hidden Power, is Sunny Day.
Also this pokemon is actually in OU. This pokemon didn't need another buff in new typing and with weaknes to Stealth Rock.
+ Flare Boost and Water / Dragon-typing
Well, this is actually my idea, what Recreant can confirm, because I send mesage with this idea for him.
Why I chosse that Flare Boost, you may ask?
Well... I really like Marvel Scale, what can be helpfull against physical atackers. Some people run this mon with Flame Orb just for that Burn ( try once, and... well, much better in my opinion is Leftovers set, but Flame Orb is situational).
Also clear water type is good in defensive aspect, and stats are amazing for good sp. tank. The problem is... Electric. Yeah, Grass is also really big problem, but in offence we prefer using types what can hit more than only three types super effective and a lot of more what are resist (seriosly - Grass is terrible in offence, because they hit SEVEN types with halved power, and some pokemons with only 1/4 power...). So... Electric is problem, because they can actually hit that Water type super effective. Four types (with one immunity) could stop this, but other fantastic in offence type - Ice - can hit from these list THREE types super effective. This is reason why people use that Electric type usually with Ice type.
With Water/Dragon typing, this Milotic takes both of them neutral, also lose this Grass type weaknes, what is nice bonus.
And we could stop here with boost for Milotic. Really - Milotic is fantastic special wall with clear Water type, even better with Water/Dragon type. Four time resist Fire and Water types, takes neutral damage from all coverage moves, gain only two other, less common weaknes in Fairy and Dragon types (okay - AND Freeze-Dry).
But... This could be boring when we just stay with that Marvel Scale and Competetive abilities (Cute Charm is definitly less usefull, and oponent must make contact with this pokemon, so.. nearly always use physical move, what means here, we can't run Marvel Scale). This pokemon must switch into intimidate user, and sometimes that intimidate go into previous pokemon. Competetive works always only, when we have Webs, or when we start first turn with Milotic (or both of pokemons die in previous turn, and both playesr must choose their pokemon for next turn). And when oponent just drop Intimidate - of corse.
Maybe we could push that sea snake into offencive plays? Because this pokemon have now Dragon type, so why not give for this pokemon bonus from Burn status but this time for Sp. Atack?
Clear Water type with Flare Boost looks... meh... okay, maybe can stay, but Dragon in fire? That angry Dragon who gain that hidden power from that burn sounds much better than fish, what... didn't want to stay outsite from water...
Also, I give this abillity for Milotic, because this is really raretly usable abillity. Only Drifblim can normally use this abillity, and he usually use Unburden anyway. Also Drifblim can't use Roost or Recover.
Of corse, this abillity give HUGE boost for sp. atack. But still this pokemon need to be burned for activate this abillity. Like in Marvel Scale, what of corse can be activate from Toxic, but usually when we run tank wihout Poison Heal... that toxic even when boost defensive stat, is the worst thing what we can have. have in mind, Milotic don't have healing from status.
This is reason why I choose this abillity.
+ Thick Fat
Okay, so let'a take two weaknes from grass pokemon. I think I saw that before...
But... This also means, this pokemon actually have better change in battle with fire starter, what shouldn't happen. All pokemon games we start from choosing first pokemon, right?
We start with Overgrow anyway, but when we give that option for Fight against type, what should be counter against him... something is not right...
Okay, in last generation we have that Fire/Psychic type, thats right, but now this pokemon need use Psychic type against him. Also, STAB for Psychic moves this pokemon gain on last stage of evolution.
In other hand we have Water/Dark type with Protean, what can hit super effective with STAB all other pokemons. You use against water type Grass? Nope, he is now Flying, in case when you use Fighting type. Also... you dead, because four time super effective flying move...
We have also that Empoleon with Water/Steel type, but in this situation he gain two weaknes what other starters from the same generation share: Fight (Infernape) and Ground (Torterra).
But more about this pokemon:
Thick fat is great abillity for him, and on physical site he can now tanks really well Fire and Ice atakcs. Sadly Ice and Fire moves usually are special.
Now we have better change with Mega Charizard X, because this guy have good defensive stat, but against Fire/Dragon Mega Charizard X...
252+ Atk Tough Claws Mega Charizard X Flare Blitz vs. 252 HP / 252+ Def Thick Fat Chesnaught: 176-210 (46.3 - 55.2%) -- 11.3% chance to 2HKO after Leftovers recovery
(46.3 - 55.2%)
He survive... one hit.
Still, he can't switch into Charizard, because he could lose to much health, and predition with Dragon Dance against Spiky Shield would cost him a lot.
But now Weavile can't deal to much damage from STAB Icicle Crash:
252 Atk Life Orb Weavile Icicle Crash vs. 252 HP / 252+ Def Thick Fat Chesnaught: 109-133 (28.6 - 35%) -- 99.4% chance to 4HKO after Leftovers recovery
(28.6 - 35%)
+ Trick Room and U-turn
This actually is big threat. In Trick Room he outspeed everything in OU expect Mega Sableye and Ferothorn - both with minimal speed. Prankster Will-o-Wisp or Taunt before Trick Room can stop sweep before he will start sweep. Also Hidden Power Fire could suprice this pokemon, but only, when oponent use against this monster good special atacker. Prankster Encore could stuck this pokemon in Trick Room, and reset his room effectivly, but who could risk switch into this beast with that power?
He can now use that U-Turn, what can be really helpfull to catch all counters (Arena Trap pokemon can trap and Knock Out oponents Fire pokemon).
From lower tiers other pokemon who can take his Trick Eoom is Mega Camerupt, with the same speed like Excavailer. That Flamethrower can really quick clear this Bug, but the same bug also have Drill Run.
0 SpA Sheer Force Mega Camerupt Flamethrower vs. 174 HP / 0 SpD Escavalier: 672-792 (207.4 - 244.4%) -- guaranteed OHKO
252+ Atk Life Orb Escavalier Drill Run vs. 248 HP / 252+ Def Mega Camerupt: 185-218 (53.9 - 63.5%) -- guaranteed 2HKO
This pokemon could use Focus Sash for one guaranteed survive - this pokemon can't be burned by Sheer Force fire move.
Really scary pokemon...