Fan Casting Gone Horribly Right in Sort by Tropes

Rather than have something unexpected happen that sabotages the program, the researchers have everything proceed in an orderly fashion. The results are everything they hoped for — better, in fact. Unfortunately, they've succeeded too well, and it's this success that dooms them. The result turns out to be too intense, too powerful, or the researchers didn't fully consider the consequences of what they wanted to do. Or, maybe they just made an awesome stealth device... that they can't find because they can't see it.