In a split second the wings went wiggy waggy and we crunched onto the runway in a most awkward fashion.
Did you start using large, rapid aileron inputs when the wings went 'wiggy waggy' during the flare? If so, perhaps the resulting spoiler movement dumped all the lift, causing a crrrrrrrrruncher. I've seen it happen a couple of times while landing in turbulence. The 777's FBW ailerons are very responsive.