Keep the parasitated girl. She got the crabs or slugs or something, but hand over that Scorpion huntress! I hope that's her natural appearance and not that she is like that cockroach in MiB1.
But dangerour humans....Imagine a species living on a world far to close to its sun. Its surface is therefore bathed in parts of that sun's unhealty EM-radiation spectrum. The atmosphere is so hot, that some solids, like e.g. metals, are either liquid or even vapor within it. The atmospheric pressure is also very thick, so that you woudn't even withstand slow winds. They'd simply drag you away. Moving within it is seriously hard even when there is no wind, because of the drag. Or maybe instead it's so thin, it's right next to vacuum, which in turn would make the suns em-radiation even more extreme. And yet there is life. Those lifeforms have aggressive chemicals as their body fluids (at least one is a potent solvent) and their body temperature is so high, they could burn though many used standard building materials, so most doors, windows and even some walls. And they are strong enough to simply walk through it, because their world is a rocky high gravity word. Yet somehow those lifeforms managed to break free form their world's surface, despite the gravity (and the high atmospheric pressure) and reach interplanetary space, by using the very primitive method of using explosives. Yet they succeed in doing so! UNREAL! They must have a very advanced knowledge of chemicals, structure building and aerodynamics to do so. Some of it escapes ours!
So they are super strong, hot, taking quite a punch of radiation and are able to come up with and use the most unreasonable methods. (They also survive the vacuum of space for a minute or so and LIVE!)
If there would be life on Titan, it might perceive Earth and mankind in such a way.
We're always an the lookout for signs of oxygen in the atmosphere of a rocky world in the "right" distance of its sun. Let's face it. We don't really know, if that's the only right distance. Maybe there is life on worlds with liquid methane, in gas giants or even in suns themselves. In the end life only needs a environment, that's stable enough to somehow support the storage of information and unstable enough, so that that information can mutate.