we were 2 on a flat world, my friend (owner of the world) is crushato and I because of a bug I stayed inside the world and created a copy of it (we were in the end, all this in creative) then exiting both minecraft (windows 10 edition) and the world that had become lan disappeared.
after that, returning to minecraft the lan world disappeared and returning to the same world we had some missing chunks and all the constructions made were gone.
then we tried to use a copy of the world, but the chunks were normal, but there was no construction except some "halfway".
finally we tried to use a backup, but it was signed: destroyed earth, lava and above all a writing of magma that said: server 000. c / e x e.
Finally my friend no longer starts minecraft.
I noticed if someone had already made a similar report, but nothing.
looking on the internet it turns out to be a crepypasta virus.
I attach screenshots.
Thanks for your help.