Darkmalice
Level 3
I have to agree with pi face that I prefer the 4 HP / 252 Def / 252 SpD spread with Blissey. It helps if Palkia manages to lay an Aqua Tail on Blissey, if Scizor switches in and she needs to take Pursuit damage, if she really needs to use Toxic on Supporting Groudon, or any suprise physical attack in general. The extra HP EVs have very little effect on her SpD, and more often than not, I find I don't need them (especially seeing as SpecsOgre will always 2HKO her).Blissey: The supreme special wall in standard play returns! With 255 base HP and 135 Special Defense, she does not need to be explained much. However, with the insanity of special attacks in Ubers, Blissey is often geared to the special defensive side rather than the usual physical defensive department. This by no means leaving the defense untouched. Blissey needs at least 100 Defense (stat) in Ubers. In Ubers, one doesn’t want Blissey to die in 2 Dragon Claws from Giratina, or OHKOed by a Metagross’s Pursuit. Also, the normal Seismic Toss/Thunder Wave/Softboiled/Ice Beam Blissey set is not very effective in Ubers. For maximum special walling capabilities, people go with Thunder, Ice Beam, Softboiled and either Calm Mind or Psych Up. Psych Up can grab stat boosts from things like Latios if he Calm Minds quite a bit, while Calm Mind lets it stat up on Pokémon who may not set up like Roar-less Giratina. Occasionally, Blissey will carry Toxic to break down walls, and this is also a reason why in Ubers there exists many a Steel-type. Blissey can also aide its team by using a Wish + Protect strategy, which can heal walling Pokémon that cannot heal themselves, like Wobbuffet and Groudon.
Also, I won't argue the mention of Calm Mind and Psych Up, but it should be mentioned that Blissey will have a very hard time trying to get stat boosts thanks to Rayquaza, Wobbuffet, non-supporting Groudon, Garchomp and other hard physical hitters.