A: There are a handful of cards which are able to get rid of certain Attaching Creepers, and the language about how this happens varies.
In Star Fluxx, both the Doctor and the Engineer say they can “detach and discard” Brain Parasites and Malfunction respectively. The “detach and discard” language does mean that the Creeper must be attached in order for them to discard it. Let’s use Malfunction as our example, for reasons we’ll discuss in a sec.
If you have Malfunction, and it’s not attached to anything, there isn’t anything Malfunctioning. Nothing is broken, so the Engineer has nothing to fix. Thematically this works perfectly, though it’s a bit harder to justify why the “floating possibility of a Malfunction” could prevent you from winning, but that’s the way it goes. Maybe you just have bad luck hovering over you, waiting to happen, and that’s enough to do it.
Note that it’s actually impossible to have the Doctor available to cure unattached Brain Parasites. If the Doctor is there, then the Brain Parasites will attach to him, and he won’t be curing anyone (of Brain Parasites, the only known health issue in the universe… or, well, the deck)
Interestingly enough, in all four of the Trek Fluxxen (Original Series, TNG, DS9, and Voyager) the language on the Engineer’s card says simply. “If you have a Malfunction, you may discard it.” With this wording, there’s no question about whether Malfunction must be attached; clearly it doesn’t have to be.
Ironically, however, without the “detach” language, technically any afflicted Keeper should be discarded with its Malfunction. However, we all know that the Engineer is supposed to fix things, not just toss them when they break, so we hope that nobody has been doing that. (So wasteful!) Just in case, though, we have an FAQ specifically for that instance. Obviously, we should have used the same language on the Trek Engineers as we did in Star Fluxx… but we didn’t. Oh well.
Finally, in Cthulhu Fluxx, we have two Keepers which can remove attached Creepers. One is the Sanitarium, which says, “you can discard Nightmares and/or Madness if they are attached to one of your other cards.” Though it doesn’t mention detaching, like the Trek engineers, nobody seems to question that the Sanitarium isn’t going to kill its denizens (though this is Cthulhu Fluxx, so…).
Lastly, there’s The Dreamer, which says, “you can detach and discard Nightmares if they are in play.” It uses the “detach and discard” language, which we’ve clarified above. (You can only discard them if they’re attached.) What’s interesting about The Dreamer is that it’s the only card like this which would let you cure someone else’s Keepers if you wanted to. This would seem to be counter-productive, but there are, of course, Goals which call for certain Creepers, so it’s conceivable that you might want to get rid of an opponent’s Creeper.