Queen's nest

The Queen's nest is found at the center of Metroid hive in Area 8 of SR388. As such, it is the den of the Queen Metroid responsible for propagating the entire Metroid species. Samus Aran enters the Queen's nest during her mission to exterminate the Metroids, leading to the climactic battle against the Queen Metroid.

There are two sections of the Queen's nest. The right side of the room is where the Queen Metroid and her hatched eggs are found. The left side of the room is where a single unhatched Metroid Egg can be found. In Return of Samus, the latter is actually loaded as a separate room (connected directly to the tunnels leading to the Surface), but is made part of the Queen's nest in Samus Returns. When she first enters the Metroid hive at an earlier point, Samus passes through a narrow tunnel directly beneath the single egg.

In Return of Samus, the Queen's nest appears to have artificial structures, likely remnants of the Chozo ruins now inhabited by the Metroids. The Metroid Egg is located in a rocky cave with three small clusters of crystals. In Samus Returns, the entire room is redesigned with a much more organic aesthetic, with the floor and walls caked with Metroid webs, and large glowing red crystal-like formations in the background. Her brood of hatched Metroid Eggs can be seen in the background, partially submerged in a pool of unidentified green liquid pouring out of smaller organic structures hanging from the ceiling. Around the unhatched Metroid Egg, there are red pustules, thorn-covered organic structures, and small green plants-like growths.

It is a fairly long room, but the Queen Metroid's bulk takes up much of the room and leaves Samus with cramped, claustrophobic quarters to dodge incoming attacks. Although Samus drops into the room through a hole in the ceiling, she cannot directly return to the room above through this entrance. In Return of Samus, there is a hole in the floor that Samus can use to escape if she needs to restock on energy and missiles; when the Queen Metroid is killed, this is covered up, preventing Samus from backtracking. In Samus Returns, Screw Attack Blocks in the ceiling allow Samus to return to the room above after killing the Queen Metroid.

In Return of Samus, Samus can enter the Queen's nest before exterminating all of the Metroid larvae in Phase 9. If this happens, the Queen Metroid herself does not appear in this room, although she can be heard roaring in the background. No music will play in the Queen's nest (or in the preceding hallway), leaving the Queen Metroid's cries as the only sound. A large cluster of crystals blocks the entrance to the egg chamber; since there is no other way out of the room, Samus must exit through the hole in the floor and return to the broken Chozo Statue room. This scenario is not possible in Samus Returns, since locked doors ensure that Samus must kill all Metroid larvae before proceeding into the next room.

After the Queen Metroid is killed, Samus walks into the left side of the Queen's nest, where she finds the last Metroid Egg just before it hatches into an Infant Metroid. Samus decides to spare the baby's life, and it assists her by clearing out crystals blocking their path back to the Surface.

While the Queen's nest can only be visited in Return of Samus and its remake, the scene where the baby Metroid hatches is revisited as a flashback in the Demo Screen of Super Metroid and a cutscene in Metroid: Other M. Building upon its original appearance in Return of Samus, these games depict the Queen's nest as a natural rocky cave with stalactites, and more hatched Metroid Eggs can be seen around the baby's egg. The scene and room is also depicted in the Other M Past is Prologue.

• "Queen's nest access"

In both games, the left side of the Queen's Nest connects to the crystal-filled tunnel network leading back to the landing site (in Return of Samus, the Metroid Egg is part of the latter room). In Return of Samus, an opening in the floor leads to a room with a broken Chozo Statue.

• 1 Infant Metroid (baby)
• 1 Queen Metroid

• The Queen's nest is the only Metroid boss room in Samus Returns that does not become repopulated with common enemies after the Metroid is defeated. It is also the only Metroid boss room where Boss Go continues playing indefinitely after the battle, even if Samus returns to the room afterward.
• In Samus Returns, although the Queen Metroid and Metroid Egg are located in the same continuous room, there is a fade-to-black screen transition the first time Samus enters the left half of the room, likely due to loading the cutscene of the baby hatching. This transition does not occur on subsequent visits.