/usr/bin/cage: invalid option -- '-'
Usage: /usr/bin/cage [OPTIONS] [--] [APPLICATION...]

 -d	 Don't draw client side decorations, when possible
 -D	 Enable debug logging
 -h	 Display this help message
 -m extend Extend the display across all connected outputs (default)
 -m last Use only the last connected output
 -s	 Allow VT switching
 -v	 Show the version number and exit

 Use -- when you want to pass arguments to APPLICATION