Be Careful When Moving Things: 3 dots instead of 2 creates magic

x@x:~/test/dir/dir2$ ls
disappear
x@x:~/test/dir/dir2$ mv disappear ...
x@x:~/test/dir/dir2$ ls
x@x:~/test/dir/dir2$ cd ..
x@x:~/test/dir$ ls
dir2
x@x:~/test/dir$ cd ..
x@x:~/test$ ls
dir
x@x:~/test$


UPDATE: It actually just changes to a file named ... it does not disappear