Unknown, unknown but presumed to be venomous (perhaps highly), and probably as escape prone as all of them !
Well, now that you have it, be sure to keep detailed records of everything...feeding behaviour, socialization, etc...it may be one of the few chances most of us will ever have to be near one.
I am a strong advocate of asking questions before buying any animal and unfortunetly, a lot about we have to say about wunderpus and the similar looking species 'mimic' is not very positive.
This is because so little is known about them, but what is known is that they tend to do very badly in captivity for the most part. And that they are normally always imported as adults with maybe only a few weeks to live.
Please have a read at this article by Chris Shaw and Dr Caldwell on the subject...