Teleport wrapping effect/Mask

Hello!

I want to create a sort of teleport for 2D game. When you enter one part of the teleport you are wrapped into other part of the teleport and player sprite should be warped between the two. Like in old nes games, you could go out of screen and you would appear on opposite side.

This picture should explain it.

https://dl.dropboxusercontent.com/u/1248743/teleport-example.png

Problem is I don't know where to start, I have limited experience with shaders and I'm not sure if masking alone would solve this.

If you can share some examples or give me some directions that would be awesome.

Thank you in advance