Rexaura

Rexaura is a Portal modification featuring new gameplay elements. It was initially released on ModDB on January 10, 2012. The mod has since been updated and re-released on Steam.

Hydromagnetic Cube Stability Unit
Cubes can be placed on the Cube Stability Unit, and any High Energy Pellet that hits the Cube will be redirected. Energy Pellets will explode if they hit the wrong end of a Cube in the Cube Stability Unit.

Story
After a new game has been created, the player watches a video of a Relaxation Pod being raised into a hole in the ceiling. Once the video has finished or been skipped (Mouse 1, double click), the announcer states that you are attending your 999th session of the Aperture Science Automated Testing.