Grimes
Yeah it's synth/rock ostinato, but it also wavers between tonality & modality... i.e., it's the only witch house music that sounds like the person making it has control over pitch AND rhythm.
Also recommended by Migporc, Ælf, pink smog and 7 others, Poop Thug Life, yendo, Vulkan the Krusader, Native Deer, decays, Cash Totals Zero and Cheese Dubstep.