I believe that thing is Monster Sue. See, this is like a cross between the scene where Misery is telling you to leave and never return, and the point after you kill the Undead Core when the place is falling apart. Misery is saying that she'll return Sue to her Mimiga form if they leave immediately - otherwise, she'll just leave her like that, only to be crushed when the island falls. Of course, this scene would be leading up to Quote going after Ballos...
Sorry, didn't see the full-sized image. Only noticed the seemingly broken jpeg posted by Mr. Johnson and made judgements based on the original, shrunken image.
Now I can safely say that THAT must refer to either Jack or the seemingly invisible thing that has tied him up and suspended him in midair by nothingness. He's struggling, so he must be attached to something up there. Also, wouldn't Quote try to save them both somehow?
I think the message Upthorn is trying to convey is that this manga, if you want to call it that, is nothing more than a parody and should not be taken seriously. The thing flying above Quote and Misery is just some random weird thing that makes funny noises at it flys. It isn't meant to be anything more than a "WTF" joke hence why Quote cannot make out what the heck it is using his computerized intelligence.
Edit: Now that you mention it, I guess it does look like Jack flailing his arms, but it is still meant to be just a joke and nothing more.
It's from the Doukutsu Monogatari oekaki bbs. I remember when it was posted. It's not part of a larger manga, although the same artist has posted one other in a similar style, as well as other pictures. I think the artist's name is "Tyuuji" （てゅーじ）, if I'm remembering correctly, which I'm probably not.
In the image in question, the dangling thing is Jack. (He looks a bit weird because the artist's trying to show the swinging effect.) I ought to explain that there's a major in-joke among Japanese DM fans where everyone pretends to forget Jack's name. Don't ask me why. (Maybe it's because he disappears from the story in the second half or something.) So the reason the manga here sounds so inexplicable is because it's a reference to that joke.
I knew about the whole "Jack turning up in strange places because he just disappeared" meme, but I never knew people started to forget his name. Is it because his presence was so pointless and irrelevant to the story that no one remembered him after he left? I thought everyone was supposed to be trying to find him though - you know, like Waldo...