When a foe megamorphs (usually when a boss is defeated), you can have a megabot fight alongside your team. A megabot base is necessary if you want to have a megabot. Once you reach specific conditions in the game (a stage/mission with the requirement of a megabot), you’ll be required and tutored on how to build a megabot base by default. Earning and Upgrading a megabot works the same way as earning and upgrading heromorph suits.
(info panel on your megabot along with help commands)
Class D Megabots (Click image to enlarge)
Class B Megabots (Click image to enlarge)
Class A Megabots (Click image to enlarge)
Class S Megabots (Click image to enlarge)