I actually had my own idea for a UFF arc with the same title ("Impossible").
My version is a stupid, relatively self-contained 2-parter. The set-up is like this: most computers in the Ultimate Universe run on an operating system known as "Portals", manufactured by a software company called "Nanosoft", which has a monopoly over PC programming. As part of the default "Portals" software, there is an annoying, animated helper called a "Popuppian" -- a cartoon alien that, well, pops up, every now and then, ostensibly to guide new users, by shape-shifting into various forms, but always retaining its characteristic purple-and-green colors.
Sue's Notebook computer -- which includes her personal notes about the DNA extracted from Zombie FF, which she is attempting to analyze -- runs on Portals software. Impossibly enough, a probability glitch causes the *information* about the zombie virus forumla to mutate itself into a *computer* virus, "reanimating" the irritating Popuppian, and causing it to project a hard-light version of itself into the Baxter Building! Why, that's Impossible!
The Building goes into lock-down. Realizing that they can only control the idiotic creature for so long, our heroes -- with the help of the Baxter support staff -- need to figure out a way to outsmart the damn thing before it completely wrecks the Building.
See, I told you it was stupid.
