Trans-Dimensional Hopping occurs when an OC suddenly travels to another world. There is usually no logical explanation for this behavior, except the wish of the author to have his/her OC interact with his/her favorite canon characters.
There are many problems with this plot device:
- The canon characters in these stories are wont to react to the meddling OC without any sort of surprise, caution, or anger that would normally accompany such an intrusion.
- The universe in which the OC finds herself is usually fraught with danger, or at the very least lacking any kind of valid identification - yet she is never arrested and is usually capable of meeting all kinds of threats head-on. (It doesn't help that she is often a young teenager.) Somehow, the OC never gets dirty, either, despite the fact that she is now essentially homeless and owns nothing of collateral value. She may not get a chance to shower, but her hair will never lose its salon-fresh gleam, her teeth never yellow, and she never has to shave her legs.
Occasionally, a responsible author will write a fanfic involving Trans-Dimensional Hopping that does not result in the creation of a Mary Sue; however, this is extremely rare.