The Metroid Prime trilogy changed a lot of familiar elements from the old games. The third-person view was changed to first-person. As a result, the games were less Metroidvania and more FPS, with the added ability to scan enemies and environments with the scan visor.
The scan visor itself allowed players to learn more about the worlds they were on and how the flora and fauna of those worlds had changed in response to the corrupting Phazon. In addition, a scan would inform the player on strategies they could use to defeat trickier opponents. As could be expected in a series like Metroid, for as informative as these scan logs could be, just as many were exceptionally twisted or dark upon being discovered.
10 The Reptilicus Were Once Intelligent And Sentient
Appearing in Metroid Prime 3: Corruption, the Reptilicus are native to the planet Bryyo and are shown to be aggressive and somewhat primitive creatures. The scan log for the Reptilicus indicates that the species was once intelligent and advanced until they began to suffer from the effects of Phazon corruption which replaced their capacity for higher thought with an animalistic bloodlust.
By this point in the series, the corrupting nature of Phazon is well documented, but it's still disturbing to see just how far a species can fall when Phazon takes its hold over them.
9 Barbed War Wasps Have A Grotesque Way Of Hunting Prey
Barbed War Wasps are an enemy in Metroid Prime and Metroid Prime Hunters. Their scan log mainly just explains how Barbed War Wasps attack, shooting their stinger at Samus from far away. However, the scan log also includes some small tidbits about the way the stinger functions that elevate the scan log from mundane to horrific.
The stinger can be shot up to 20 meters away and only takes a few seconds to grow back before it can be shot again. Finally, and most disgustingly, the stinger is used to secrete a substance that predigests the wasp's prey. It's proper body horror to imagine some unsuspecting victim getting hit with a stinger only to slowly melt into a puddle for the War Wasp to ingest.
8 Liquid Phazon Can Bring The Dangers Of Phazon Right To Your Front Door
Liquid Phazon makes its one and only appearance in Metroid Prime 3: Corruption, and its scan log demonstrates perfectly how terrifying it is. Liquid Phazon is described as being semi-sentient glob of Phazon that is capable of reproducing. It can alter its shape in a limited capacity and exudes a toxic chemical that protects it from threats. While not mentioned in the scan log, if Samus touches Liquid Phazon while in her Morph Ball, she'll be damaged by Phazon, suggesting these puddles carry all the typical dangers associated with Phazon.
On its own, Phazon is a dangerous substance capable of destabilizing civilizations like the Reptilicus. Combining those dangers with a mobile form makes Liquid Phazon a terrifying concept.
7 The Phazon Elite Makes An Awful Trade For Power
Only one Phazon Elite is ever seen across the trilogy, but it's certainly a memorable encounter. The Elite is a hulking space pirate with bulges of Phazon scattered across its flesh. When scanned, it reveals that this particular Space Pirate was interfused with Phazon, resulting in its massive strength increase. This isn't the only thing the Phazon drastically changed, though, as its lifespan has also been drastically reduced by the process, and the Space Pirates responsible for creating the procedure don't care.
The Space Pirates aren't exactly the most caring bunch, but this suggests a new low for the pirates. Even though only one Phazon Elite is ever seen, the idea that the pirates both have the technology and the will to sacrifice their own for more power is chilling.
6 Fission Metroids Double The Danger Of These Parasites
Fission Metroids are one of a number of new variants of the parasitic alien that make their debut across the Metroid Prime trilogy. The scan log for the Fission Metroid in particular, though, reveals a great deal of danger from this particular variety. The log states that Fission Metroids are a mutated variant brought about by Phazon that are capable of splitting into two separate entities and are immune to all types of weaponry except for one randomly determined weakness.
Metroids are already dangerous enough when it's just one creature with an ice weakness but randomize that weakness and then make every one Metroid two in disguise, and there is the recipe for a plague of parasitic jellyfish that could easily be the scourge of worlds.
5 The Chozo Ghosts Are Haunting In More Ways Than One
One of the sadder but still dark scan log entries revolves around the Chozo Ghosts. These entities are the spirits of Chozo that have been driven mad by the effects of the Phazon corruption on their homeworld. They are drawn to Chozo religious sites where they attack anyone who enters the area. Seeing the effects of Phazon on the species that raised Samus is hard enough, but seeing how it won't even let the dead find peace makes it even darker.
The way these spirits flock to religious sites suggests they still hold some semblance of who they were in life, making it even darker as they aggressively attack Samus and anyone else who dares disturb them.
4 Twilight Is A Dark Ending To The Luminoth's Story
Throughout Metroid Prime 2: Echoes, players can find and enter into the scan log information about the history of the Luminoth, a race of moth-like creatures who settled the planet Aether long before Samus arrives there in-game. 'Twilight' is the final entry in the scan log in a series of entries revolving around the Luminoth's history with Aether and their fight against the Ing. This particular entry details how the last of their species entered stasis pods to avoid being killed or possessed by the Ing while one lone warrior stands guard over them.
It's a short, but chilling cliffhanger to the story of a species of aliens that are shown to be peaceful and similar in nature to the Chozo fans are so familiar with.
3 The New Terror Has A Shocking End
Another scan log entry revolving around the history of the Luminoth, 'The New Terror,' describes as the Ing began possessing Luminoth and using them as weapons against their own people. The story is already disturbing, but what pushes this log entry over the edge is the end. The author says that, should their shields fail, all the Luminoth were prepared to self-terminate in order to avoid being taken by the Ing.
It's a chilling moment, as it gives players the full context of the threat the Ing posed to the point where every Luminoth was willing to put an end to their own lives in order to avoid a worse fate.
2 The Stellar Object Reads As Being A More Final Entry Than It Is
The Stellar Object is an early entry in the scan logs revolving around the history of the Luminoth and tells of a large object hurtling through space directly towards Aether. It describes how the Luminoth attempted to use many weapons in order to divert its path to no avail. Finally, it ends with the Luminoth hiding in bunkers as they await the destruction of their world and themselves.
The whole entry actually describes how the Ing made it to Aether. However, it reads like someone's final journal entry before an apocalyptic event, with the finality and resignation of whoever wrote it adding to how dark the entry ends up being.
1 Leviathans Are Responsible For Spreading Phazon Throughout The Galaxy
In Metroid Prime 3: Corruption, players are able to scan an infant leviathan and learn more about the species. The scan reveals these creatures are launched from Phaaze, a planet that is the origin of Phazon and what spreads it across the galaxy. They also learn that when an infant leviathan reaches maturity, it is sent to another planet where it crashes and dies. After its death, a local predator is drawn to its body, where it protects the Phazon core housed within its corpse. Eventually, the core sinks into the planet and warps the ecosystem into one based around Phazon.
It's easily the darkest log entry in the trilogy as players learn the way Phazon spreads from planet to planet and the parasitic nature inherent in its spread.