The Martians

The Martians are introduced in the Season Three episode King of Mars. They are on top of an Aztec-structured pyramid guarding hydro-quantum energy source on Mars. Originally, they are presumed to be large stone carvings. However, they come to life when Eustace and Jimmy were fighting for the power source. The Martians were tired of Earthlings acting like Mars was theirs. They were sick and tired of earth sending probes and spacecrafts to their planet and slowly trying to conquering it. The Martians decided that the only way to stop them invading was destroying Earth.

Eventually, Jimmy and Eustace realize that the only way to get out of the trap and save their home planet was to stop fighting and work together. They get out of the trap via slicing it with their swords and reconfiguring the IPMS to make it rain. The Martians are allergic to the rain on Mars and gave Jimmy a portion of the power from their hydro-quantum energy source and promised not to destroy Earth.