SSH command has no -Z option - Obfuscated ssh client
Problem sovled. You can download obfuscated-openssh and compile it in MacOS to get a new ssh command.

Download it from https://github.com/brl/obfuscated-openssh.

Download and install gcc - http://www.mkyong.com/mac/how-to-install-gcc-compiler-on-mac-os-x/

$ sudo ./configure
$ make


If there are some errors while compiling it, remember to check this  https://discussions.apple.com/thread/2546848?start=0&amp;tstart=0 (see details below)

$ export LDFLAGS="-L. -Lopenbsd-compat/ -fstack-protector-all -mmacosx-version-min=10.4 -lresolv"
$ ./configure
$ make


All done, you will have a new ssh. Check version.

$ ./ssh -v
OpenSSH_5.2p1, OpenSSL 0.9.8r 8 Feb 2011
usage: ssh [-1246AaCfgKkMNnqsTtVvXxYyz] [-b bind_address] [-c cipher_spec]
           [-D [bind_address:]port] [-e escape_char] [-F configfile]
           [-i identity_file] [-L [bind_address:]port:host:hostport]
           [-l login_name] [-m mac_spec] [-O ctl_cmd] [-o option] [-p port]
           [-R [bind_address:]port:host:hostport] [-S ctl_path]
           [-w local_tun[:remote_tun]] [-Z obfuscate_keyword]
           [user@]hostname [command]