Ruins Test

The Ruins Test appears in the Chozodia temple in Metroid: Zero Mission after a suitless Samus Aran invades the Space Pirate's base. It appears as a ghost-like entity representing a Chozo warrior wearing a variant of the Varia Suit. The entity holds a floating orb containing an image of either Samus or a hieroglyphic-like symbol. The Ruins Test can only be damaged while its sphere is showing the symbol; if it is shot while displaying Samus, she will take damage instead. It will also shoot lightning, which will travel along the ground and must be jumped over. The Ruins Test takes four shots to defeat. The hieroglyph speeds up after each successive shot making it harder to hit as the orb only reverts to the symbol for a short time and getting a shot in can be difficult. After its defeat, Samus receives the "legendary" Power Suit. Also, the three Mystery Items collected throughout the game are revealed to be upgrades; specifically the Gravity Suit, Plasma Beam, and Space Jump.

Note that, before the battle, a cinematic shows what appears to be a younger Samus viewing the same wall paintings shown during the boss battle, suggesting that she has visited the room while living with the Chozo.

Interview

 * "Why does her suit come off when Samus is escaping inside her spaceship?" 

Yoshio Sakamoto: "For Samus's suit to appear, considerable powers of concentration are necessary. In short, it was too constraining. It's the same as a salary man loosening his necktie when returning from a business trip on the bullet train." 
 * "In this version when you first pick up the Varia suit, the suit doesn't change, why is the Suit that Samus puts on incomplete?"

Yoshio Sakamoto:"The Power Suit that Samus wore in the first half was not the Legendary Power Suit. In the Legendary Power Suit, the Varia Suit gains efficiency and so its form changes." 


 * "Isn't Samus's powered suit integrated with her whole body? After you destroy Mother Brain, and on the way back pursued by space pirates, Zebes is falling apart. Why does she lose her suit when it should be integrated with her. That's my first question. Thank you very much!"

Yoshio Sakamoto: "For Samus to remain connected with the Power Suit requires mental energy unfathomable to an ordinary person. In situations like this when she is under pressure, indeed, even Samus is unable to concentrate her mental energy. However, when Samus completes the trial of the spirit of the mural (God of War), she regains her strong force of will and can successfully integrate with the Legendary Power Suit." 


 * "Why is power suit in the beginning different from the Legendary Power Suit? Is it the same one granted by the Chozo?"

Yoshio Sakamoto: "Only the chosen few can wear the Legendary Power Suit. Those who prevail over the trials of the spirit of the mural (God of War) can integrate it within their body." 

Trivia

 * The Ruins Test appears to be wearing a power suit from at least the waist up due to its shoulders resembling those of the Varia Suit.
 * It is highly possible that the Chozo that accompanied Samus during the cinematic before battling the Ruins Test was Old Bird from Metroid (manga). This can be implied even further by the fact that the appearance of Samus in the cinematic looked similar to, if not exactly like, the time when she was three years old in the manga.
 * After completing the game, it is revealed that Samus had made a small engraving on the base of this when she had lived on the planet. (Though, it can be seen at a distance during gameplay.) The image is of herself, Old Bird, and an unknown Chozo that may represent Gray Voice.
 * The mural may be a god to the Chozo, as suggested by the Japanese name in an interview, God of War. This could be supported by the fact that it looks like the other Chozo carvings are giving it offerings.
 * The Ruins Test served as inspiration for Dark Samus, another mirror image of Samus in Metroid Prime 2: Echoes.