Set: SubRoost Lugia

Lugia @ Leftovers 

Trait: Pressure 

EVs: 252 HP / 176 Def / 80 SDef 

Impish Nature (+Def, -SAtk) 

- Substitute 

- Roost 

- Toxic 

- Dragon Tail

Ubers deserves more attention. It's definitely not balanced, but its unique banlist status makes in the only completed tier. This means that a lot of things are broken, and one good set can turn the game around more than it can in lower tiers.

SubRoost Lugia is a concept that builds off Lugia's giant bulk and access to Pressure and Roost. Substitute prevents opponents from crippling it with status ailments, while Lugia goes on to stall out enemies with its SubRoost Toxic strategy. This set is somewhat effective alone, but with hazards it can be nearly unstoppable.

The first thing to stand out about Lugia is its bulk. It can survive any attack from Extremekiller Arceus after a Swords Dance, and even most super effective hits will fail to KO. Lugia also makes for a great check to most Groudon, since it can easily survive Stone Edge and stall it out with Pressure.

Substitute is the key move on this set, giving Lugia a way to dodge status ailments. This lets it beat special walls like Blissey one-on-one. Roost heals Lugia up easily and makes it really difficult to take down. Toxic is used for most offensive threats; any time you get a safe turn against something like an Arceus or Dragon-type, you can go for a Toxic to cripple them. Dragon Tail is excellent with hazards, and does a pretty good amount to opposing Dragon-types.

Of course, the most important thing to pair with this set is an entry hazard user. Ferrothorn and Forretress are some good choices for partners. That means a spinblocker will also be needed. Giratina-O is one of the best options for the role; it even has access to Dragon Tail to form a dual phazer combo with Lugia. Although it plays a defensive role, SubRoost Lugia can clear through a lot of teams alone.