Try 117 sp attack and 85 sp defence those are the lowest possiable stats.
The videos actually do unaffected stats. No IVs and no EVs. Its the base and that's it.
From what I can tell, initially I was wrong. Now that I get to sit and do the math myself rather than using the calculators presented on Smogon. It is true that you cannot deal 100 points of damage, though as I had said, that Sylveon had to be a low level, at least half that of Hydreigon to do that kinda damage with a base of 60.
The calculation the guy gave was much simpler than what I just did, though I read the harder one easier than his.
Though I have no idea what his "Initial Damage" thing is so I have no idea how he had gotten the numbers he used.
Using the minimums anyway...x4 is 195-230
x2 is 97-115
Really the minimums barely changed anything...though it does kill of the ability to use that guy's calculation to reverse check it.
EDIT: Applying the guy's formula to the one above....You can't get the numbers I got but it doesn't look like I missed anything. I don't know who is using the right formula now....
Using another Smogon one...This one is so much easier to use omg.
Using Bug since they haven't updated Fairy.
0 SpA (custom) (Move 1) vs. 0 HP / 0 SpD (custom): 96-114 (63.15 - 75%) -- guaranteed 2HKO
(96, 96, 98, 98, 98, 102, 102, 102, 104, 104, 108, 108, 108, 110, 110, 114)
Attacker Info
Bug
SpA=125
Bug Special 60 Bp
Lv 50
Defender Info
Grass
HP=92
SpD=90
lv 50
0 SpA (custom) (Move 1) vs. 0 HP / 0 SpD (custom): 192-228 (126.31 - 150%) -- guaranteed OHKO
(192, 192, 196, 196, 196, 204, 204, 204, 208, 208, 216, 216, 216, 220, 220, 228)
Attacker Info
Bug
SpA=125
Bug Special 60 Bp
Lv 50
Defender Info
Grass/Psychic
HP=92
SpD=90
lv 50
0 SpA (custom) (Move 1) vs. 0 HP / 0 SpD (custom): 84-100 (55.26 - 65.78%) -- guaranteed 2HKO
(84, 84, 84, 84, 88, 88, 88, 88, 88, 88, 96, 96, 96, 96, 96, 100)
Attacker Info
Bug
SpA=125
Bug Special 60 Bp
Lv 32 to 34
Defender Info
Grass/Psychic
HP=92
SpD=90
lv 50
As far as I can see only thing that rings true is x2 damage cannot do 100 points of damage to them. It has to be x4 to deal 100 points of damage. So it looks as if Fairy is SE to Dark with this. I find it hard to believe myself and I just did the math. Gardevoir must have been a fairly low level which is a little unprecedented.
So Fairy:
Weak to Poison
Strong against Dark, Dragon, Ice
Unconfirmed:
Weak to Steel
Strong against Fighting
Resisted by Fire/Psychic
Resists nothing
Immune Dragon
Still highly doubt the last one as its too much.