Alien Invaders 4: Hydronix - Destroyer of the Deep
Max Silver
Five awesome aliens have been unleashed from the darkest corner of the galaxy – and they’re out to destroy the universe. Only Cosmo, a young boy from planet Earth, has the power to stop them. Recruited by the elite defence organisation G-Watch to defend the galaxy, Cosmo must prove himself and commence battle against the deadliest aliens in space.
Reviews

It was very cool with all the battles and action and cool aliens
General Neptune Mystery 04.09.2021

Very good series
Master Gargoyle Bojangles 01.08.2020

I like that cosmo can change into a alien
Coach Bart Archway 26.08.2019

The book was really interesting, but they could've added more monsters to this book.
Anonymous 09.08.2017

This is a lovely book.
Anonymous 30.08.2014

I didn't like it kidding Epic
Anonymous 23.06.2014

I think this book is scary because there are deadly alien invaders.
Anonymous 20.06.2014