The description of a Xorn in the first Monster Manual makes it sound almost like an earth elemental or a construct - a "stonelike" body, "stone-lidded eyes" - so I thought I'd take it away from the twisted, frog-like depiction in the illustration and more towards my preferred chunky, geometrical look. If the arms were segmented they'd remind me of those Laputa-esque robots in the fleetway Sonic comics.
The description of the Xorn's Earth Glide ability is kinda weird as to how you might visualise it. As with the Phase Spider I'd need to animate that blue-edged glow to properly communicate how it's meant to look! Maybe one day.