Spanner, eh? First off, I think his name sounds..pretty cool. Now, looking at his general appearance, I'd like to note that he has, obviously, some kind of white-ish armor. But, what I find interesting about this armor is that his helmet design (the face area, mostly), is somewhat similar to that of the helmets some Plumbers wear. Does anyone think he could have a connection to the Plumbers? Also, the little wrist-launchers..blasters..whatever, that he has on, fire a green energy blast. What I find interesting about this energy blast, is that it is ALSO similar to the energy blast fired from the Plumbers' weapons. So, there may be a connection between him and the Plumbers. Now, I am not saying that he is a Plumber agent, or is directly tied with them. But perhaps, there's some sort of a connection. Plus, the Rooters, or the Black Ops wing of the Null Void Plumbers, are set as villains for some point in the future. On their page, it states that the Rooters are secret. Maybe, just maybe, if Spanner is connected to the Rooters, the reason why he disappeared after saving Ben, instead of helping him fight, is because he wanted to make sure that Ben couldn't ask a member of the Plumbers (most likely Grandpa Max), about him, and then try to seek out more information about him, causing suspicion.
Well, I think I'm done stating my speculations for now.