Kidnapping

Kidnapping is the act of stealing a person away without their consent, or the consent of the people in charge of them.

While actual children are possibly easier to kidnap (though not necessarily easier to deal with after taking them), many fanfic writers instead focus their eyes on Canon characters.

Trans-Dimensional Snatching is a subset of kidnapping.

Kidnapping is both a Real World crime and a PPC charge. As such, it is highly recommended that you do not kidnap anyone, as it is a very bad idea.