Gachiin headless (Mist Forrest in Ashina Depths) occasionally does big leap attack which results in full body slam. obviously as a distant attack. if his conjured mist is still on it's undodgeable, so probably blockable and deflectable. only saw it once though. it's possible to jump over his teleport 360 swipe, but VERY precisely. and sometimes his hitboxes are just off anyway (on wrists, on elbows, on belly, even if sword itself isn't there yet). Mist Raven does rather good job as well, but does not always provide clear warp behind him because he's kind of twitching all the time so warp-forward isn't exactly "straight forward", which gives behind-ISH effect. still good to do some beat up.