If you want to picture alien life forms, perhaps you should stop picturing them at all.
Consider the fact that 95% of the universe is actually invisible to us, hidden in the forms of dark matter and dark energy, there's a pretty good chance that that's where all the aliens are at.
We cannot detect this stuff with our senses nor our most advanced technology, we can only infer its existence from the effect it has on the tiny sliver of the universe we can see. If we cast our minds back to the discussion we had about super-senses, it might be utterly mind blowing to our alien friends that we are completely unable to see whatever it is that dark matter is made out of. To them, it would be the stuff of the everyday.
What's more, they might not be able to detect our comparatively rare "normal" matter and could be pondering what that missing 5% of the universe could possibly be hiding.