In the 10.0 update the Terrobyte no longer spawns on the map for free, you have to open your phone and ring the Purchase/Modify Command Center Contact, after this a menu will apear then enter the Purchase a Command Center Menu, after this there will be 3 options, one for MOC, one for Avenger and one for Terrobyte, To purchase click on the Terrobyte button and your Terrobyte for the character that you are playing as will spawn around you.
This mod allows you to use the Terabyte Command Center, just like in GTA Online, you can access the Oppressor MK2, and Oppressor, you can opperate a mobile drone for recon and much more.