My favorite set in all of ubers.
Lugia @ Leftovers
EVs: 252 HP / 176 Def / 80 SDef
- Thunder Wave
This is the best set for paralysis support. This uses the same EV spread as the Great Wall set, to maximize mixed bulk. With Multiscale intact, Lugia is not OHKO'd by any hit in ubers (except a few attacks from turboblaze and teravolt Pokemon, which negate multiscale). It can even beat non-specs kyurem-w one-on-one, as Ice Beam does not OHKO, and Lugia can proceed to T-wave and roost-stall Kyurem, taking less damage due to Roost's mechanics, while waiting for Kyurem to get fully paralyzed; then, it can just phaze kyurem out. Note that specs kyurem-w will OHKO with Ice Beam.
Generally, once the Lugia is up against a paralyzed opponent, it can simply continue using substitute and roost until the opponent becomes fully paralyzed, then use roost once (without the substitute breaking due to multiscale and often being "grounded"), and then phaze the attacker. For example. Lugia's substitute can survive Mewtwo's ice beam after multiscale and roost, and can therefore just phaze it away.
Since it has no attacks, it fails against taunt leads such as deoxys-s, and also darkrai leads. However, it can beat non-lead darkrai if it has a substitute up, as it can paralyze then phaze darkrai.
This Lugia should be used on teams with a slow sweeper or wallbreaker, in order to allow the wallbreaker to outspeed the opposing team. In fact, this Lugia is one of the best teammates to Specs Kyogre.
While Lugia is effective at spreading paralysis, a smart opponent will continually switch back into a paralyzed pokemon to avoid having the rest of the team paralyzed. Therefore, stealth rock is a necessity, and spikes help too (though toxic spikes prevent the spread of paralysis). This makes ferrothorn a good teammate for Lugia. In addition, a spinblocker is also important to stop the hazards from being removed, since Lugia itself can't do anything to a spinner. Rapid spin support from Keep in mind that Lugia usually loses to darkrai, and all common spinblockers also lose to darkrai. This means that a safe switch-in to darkrai is essential. RestTalk Kyogre is able to switch in easily, whereas Scarf Heracross provides a more offensive counter. Fighting Arceus can also switch in safely.
Lugia hates any sort of status, so cleric support is helpful. Chansey is able to use Heal Bell, and is also able to effectively wall Kyurem-W, something no other pokemon can claim.