The Omnitrix Expansion Pack was created by Ben 10,000. Knowing that his younger self would need it during the Mighty Invasion. He loaded it with hundreds of aliens and swent it back in time,beacuse he did not have enoguh time to make the trip himself,becasue he knew that the Aliens would attack Earth soon as well.
when he sent it back,it apeared in Bens's hands. There was a note attached that read.
Ben, I know you will need this soon,
You implement this int oyour Omnitrix by inputting the code given on this package,
Best of Luck, Ben 10...
Be used this in the invasion to hold off the aliens at the Front of battle, taking them all down by himself.
If you want to add a alien here yourself,feel free to add one here