This is more for me than others. Sometimes I forget things like this.
SSH Dynamic Socks Proxy for the browser.
ssh -D 8888 mario@example.com Browser: Socks Proxy localhost 888
SSH Tunnel to another host
ssh -L 9090:localhost:9090 user@proxyhost -i SSHKEY ssh -L 9090:localhost:9090 -N user@TARGETSYSTEM