Shadow Force is Arceus's most powerful physical move but Lugia can foil that by Reflecting on the charging turn. Shadow Force is fairly easy to play around.
+2 Shadow Force will OHKO Ghost Arceus though so it needs to be faster. Having an unfortunate Dragon weakness will hamper most walls. Most walls other than Giratina probably suck if they have a Dragon weakness because Dragon types are so common in Ubers.
<&GreatSage> if nothing else it's a "trickroom teaches pokemon" thread
<&GreatSage> which is reason enough to keep it
<@Colonel_M> I once heard Jibaku considered Scarf Gyarados for his Ubers team
<syrim> Trickroom the ultimate synguuest