A new, trendy, cyberpunk way of telling someone to fuck off.
"Shock off" can also be combined with the phrase "before I download myboot.exe into your mainframe" to express extreme anger over the recipient's presence, but it is mostly used purely to demonstrate one's extensive knowledge of obscure cyberpunk references.
The implied meaning of saying this is that you believe you are living in a fictional dystopian world in which everyone has a "mainframe" implant controlling their thoughts and actions. By downloading "myboot.exe", a virus of your own creation, into their mainframe, you take control of their mind. This is considered the ultimate threat, although very few hackers have been able to successfully pull it off, and the details on how are kept secret from all but the most elite cyberspace warriors.