Failed print

I left this to print over night, after I saw that the bottom layers were OK. As you can see, it first shifted dramatically (inches), then printed for a while, then shifted again, and then finished the print.

Any thoughts as to what might cause this kind of failure? I’ve seen minor shifting before, but never major shifting. It usually results in total print failure.

Skipped steps on the xy axis most likely

Could be loose belts, printing too fast, nozzle crash or an issue with the actual Gcode

Those are just ideas off the top of my head