To make his monsters grow, Messogog would activate the Hydro-Regenerator, summoning a rain cloud in the skies which would pour down rain upon the chunky monster remains. The rain would revitalise the parts and make them clump together, making them expand and reform into the giant monster.The Hydro-Regenerator was presumably built sometime after Tommy Oliver attacked Messogog's Island a year before the events of Dino Thunder since the entire island was seemingly destroyed by that event.
The Hydro-Regenerator was first seen being used to grow Birdbrain after his failure to destroy the Dino Thunder Rangers and would be used to grow almost every monster after that.
The Hydro-Regenerator can also work on monsters that weren't created by Messogog or his flunkies, such as when he grew Tutenhawken.
The Hydro-Regenerator was destroyed when Messogog's Island was obliterated by the Triceramax Command Center Truck.
- The only monsters not grown by the Hydro-Regenerator were Goldenrod (who made himself grow), the 2nd White Terrorsaurus (who grew himself giant instead), the third was Fossilador (who made enlarged himself) and Fridgia (who never grew as she was her own seperate entity and never associated with Messogog).
- Unlike in Abaranger, the Hydro-Regenerator is not a fruit and instead a machine.