Fast phasing Lugia (you heard it here first)
Lugia @ leftovers
Evs: 96 HP / 80 Def / 80 SpD / 252 Spe
I call this set Fast Phasing. The idea is to take a hit and then phase the opponent out. After that you rest Lugia to heal off the damage and use sleep talk for the two turns of sleep. Using sleep talk allows you to bypass the -6 priority that dragon tail and roar both have, so Lugia takes no damage for the two turns that it has to phase. Obviously having stealth rock and spikes up is important, so if they have a spinner take it out before attempting this. The ev set is meant to increase speed and defenses as much as possible, though rest-multiscale will protect you better than anything else. naturally this has no finishing power, so use it in the middle of the battle. (Works great with extreme killer arceus
The weaknesses of this set are, faster pokemon, priority, and taunt. Faster pokemon, (like Mewtwo, Darkrai, or Arceus) can be a problem but you can generally phase them out without too much trouble. Also most scarfed ubers outspeed Lugia, but if multiscale is up it can take most hits, most notably a boltstrike from Zekrom. Priority can be an even larger problem because it defeats the speed phasing idea and breaks multiscale, leaving Lugia exposed (well sort of, it still has its absurd defensive stats). Taunt stops this set dead in its tracks, so watch out for Thundurus and Deoxys s and a, though you can always switch out. Also regenerator generally prevents this set form working effectively, though only for the pokemon with that ability.
So give it a shot, it's pretty easy to fit on any team with a poke that sets up hazards, and it generally frustrates people.
Look, a three-headed monkey!