Pack-rape, also known as gang-rape, is rape with lots of assailants and a significantly smaller number of victims (usually only one). Particularly horrific, since there's very little the victim can do about it. A competent fighter might be able to fight off one assailant if not somehow restrained or disabled, but several assailants could easily overwhelm anyone who doesn't possess superpowers that involve becoming intangible or effectively nuking everyone in the immediate vicinity to death. This is not something most people want to read about, but inexplicably, it is sometimes used as a plot device and an excuse for hurt/comfort. This tends to be bad.