Example: touch -- -thisfile
The concept is pretty much the same as on how you would delete,move,edit files with a leading dash.
Example: rm -- -thisfile
mv -- -thisfile
vi -- -thisfile
This is handy if for example you have sites that needs id verification from site rating providers etc.
It's one of those days when you really need to get things done immediately but you have to browse the Internet for some answers. Cheers!