Nobody expects the magic-damage regular attack mres shredding AP Carry Soraka 8D
I forget the item build for that, though. I know it involves Madred's Bloodrazors, so you should immediately know its a joke build.
Then again, this is Soraka we're talkin about here.
Actually I kinda want to do something like that after thinking about MRES mechanics last night (due to talking to someone about how Morgana should probably build Abyssal Scepter instead of Void Staff, at least around her level)
Get Malady to combo with Starcall for absurd MRES shredding by using auto-attacks between Starfalls, then take advantage of it with either a highly AP build (Abyssal Scepter, Rod of Ages, Rabaddon's, Lich Bane, ___ boots) or an ASPD-with-magic-damage-side-effects build (Ionic Spark, Wit's End, Madred's Bloodrazor, something to help her durability [either Trinity Force or something offering Armor+MRES like Guardian Angel], boots).
It could maybe work? Silly as fuck of a build but hey~