@Boondocker: I think you did a calculation error for Turn 4?
At the end of turn 3. Shaymin has 81.25%. Leech seed recovers 14.5% of Shaymin's health (Suicune has 404 HP, divided by 8 = 50. Shaymin has 345 HP. 50/345 = 14.5%). Leech Seed recovers 6.25%, so that's 20.75% recovery in total. 81.25 + 20.75 > 100, so Shaymin has 100%, minus 25% toxic damage is 75%, not 68.75%. So Shaymin should have 75% at the end of turn 4.
More importantly though, if on Turn 5 Suicune used rest, it obviously didn't use Ice Beam, so Shaymin wouldn't be at 27.55%. It would have been at 75+20.75-31.25 = 64.5%.
After Turn 6, Shaymin is at 64.5 + 20.75 - 37.5 = 47.75
After Turn 7, Shaymin is at 47.75 + 20.75 - 43.75 = 24.75.
Turn 8, Shaymin KOs.
Also, Psych Up goes through Sub. (
http://www.smogon.com/dp/moves/substitute Fifth paragraph... also, I already knew and can verify that that's what happen anyways, from playing battle tower, Psych Up Magnezone and Umbreon so anoying...).
...
I was thinking something like Suicune @ Leftovers with Icy Wind / Calm Mind / Blizzard can actually beat Shaymin (I was having a hard time with this one before, and then I thought I got it down if Shaymin uses Psych Up whenever it gets Icy Winded.
Well, the reason why Shaymin HAS to Psych Up after being Icy Winded (or Calm Mind) is that after a Calm Mind, Icy Wind + Blizzard will KO Shaymin.
So if Shaymin does something, and then Suicune Calm Minds, Shaymin has to Psych Up next turn (unless it can KO with seed bomb, obviously), or else Suicune can Icy Wind + Blizzard. But if Shaymin used Psych Up as Suicune used Icy Wind, then it will get back to neutral Speed as well as copying the Calm Mind (so next turn Blizzard won't KO).
Likewise, if Suicune uses Icy Wind, Shaymin has to Psych Up next turn, or else Suicune can Calm mind and then KO Blizzard the following turn whereas if it used Psych Up, it'd psych up the Calm Mind and get back to neutral speed).
O yeah, and it's not like Shaymin has to continuously spam Psych Up if Suicune keeps using Icy Wind (if it did Shaymin will lose). It only needs to do it once... Better explained with scenario:
Turn 1: Leech Seed + Icy Wind.
Turn 2: Icy Wind + Psych Up. (Shaymin is back level ground and can Seed Bomb for damage next turn)
Or
Turn 1: Leech Seed + Icy Wind.
Turn 2: Calm Mind + Psych Up. (Same as above, except Shaymin takes even less damage)
Or
Turn 1: Leech Seed + Icy Wind.
Turn 3: Blizzard (55.7% max) + Psych Up. (Shaymin is back on level ground and can Synthesis to entirely nulify the damage from Blizzard since 55.7% means <50% after leftovers and leech seed).
... ... ...
Hm, I think I just found a way Suicune can beat that Shaymin though.
Modest @ Expert Belt (or ice plate or nevermeltice, etc)
252 SpA 252 Def
- Ice Beam
- Icy Wind
- Blizzard
With Expert Belt, Ice Beam followed by Icy Wind + Blizzard will KO Shaymin, assuming Shaymin uses leech seed first turn.
Blah... haha.
... maybe Shaymin needs an offensive set. Hm, this is interesting (but annoying) since Shaymin can run so many sets lol.