Life - 2000
Defence - normal
Power - 3000, regenerates, but he then uses it to blast you with arm lasers that hits instantly, but they will leave trail of light, emptying power bar
Special trait - has super armor that you can break by using strong attacks
VS Samus win animation - slowly hovers closer to Samus before either crushing her with arms or blasting with lasers (animation goes from Samus` perspective/point of view/view)
Other - all of his attacks are aerial ones, he can`t crouch or stand and he will always has faceplate on even while dieing in explosions (what is, unlike other exploding bosses, easily explained by him being cyborg/robot)
Moveset:
Light punch, medium punch - strikes with one of his arms
Strong punch - slams with both of his arms
Kicks - shoots lasers from upper part of his arms (light), mid section (medium) and lowest part (strong) of his arms
Specials:
??? - Charge - Charges at the target
??? - Gravity increaser - uses gravity manipulator to slow down opponent for few seconds if light or medium version is used, slams target against ground if strong version is used or just forces them to lie down quickly
Hypers (both are using 3 power bars:
Start - Oblivion - Spins around, quickly shooting lasers, used if has more than half of healfbar
Start - Desperate Hour - Uses gravity manipulator to stop target in the same way as strong gravity increaser, but this last for longer and slowly crushes target, used if has less than half of healfbar

Life - 1500
Defence - normal
Power - 3000, regenerates
Special Trait - can be stunned if hit in the head during hard kick
VS Samus win animation - looks at the Samus before biting camera/Samus` head
Other - can`t crouch or jump
Light Punch - swings her neck sideways (can be comboed into medium punch)
Medium Punch - basicly neck uppercut (can be comboed into hard punch)
Hard Punch - slams her head down, unguardable
Kicks - just bites, stronger if B button is used, becomes throw if C is used
Specials:
??? - Fire of the Beast - charges up plasma before releasing it in short stream (if light version is used, she aims at the floor, if medium - aims straight, if hard - aims up)
??? - Behemoth Charge - rams at the target, goes faster if stronger version is used, trips opponents, can be guarded only on the ground
Hypers (all of them are using all power she has):
??? - Serpent Flame - charges up plasma before releasing it in a stream of fire, deals 300 damage, 150 if guarded
??? - Bone Duster - charges up plasma before releasing it in a powerful stream of fire, dealing 700 damage (500 if guarded), can be used only if health is lower than 500
??? - Soul Harvester - lunges her head and after some time, bites target. If hits, she will drain them off their life force, killing in the process. Unguardable, throw, can be used if health is lower than 200. Always aims staight. Would be good if it would trigger special drained animation, but i doubt someone else would make such...or..?

Life - 1000
Defence - normal
Power - 5000, same "rage" system as Ridley`s that doesn`t allows him to use it if he has more than half of healthbar after 1st round
Special trait - can hover for some time by jumping twice
VS Samus win animation - Roars at the sky/ceilling before blasting camera with his eye laser.
Other: none
Light Punch - swings arm sideways
Medium Punch - swing arms downward, slaming target into the ground
Hard Punch - swings arms upward, can lift up into the air lying down targets
Light Kick - uppercuts with one of those things on top of his head
Medium Kick - uppercuts with another of those things on top of his head
Hard Kick - overhead slam with both of those thingies
Crouching attacks are same as standing, except hard and light punch are reversed
Aerial attacks are same, but aimed lower with stronger button
Specials:
??? - Eye of Horus - shoots laser from his eye, angled by pressing stronger buttons
??? - Seeker missiles - fires few seeker missiles (i have no idea how that is possible, but who cares, its canonical!)
??? - Piledriver - grabs opponent with long arms, if succesful, jump up and slams target head first
Coming soon...

Nightmare (ナイトメア Naitomea?) is described as a "a Bio-Mechanical organism designed for military applications that possesses uncommon power and can manipulate gravity". Nightmare appears as a boss in both Metroid: Other M and Metroid Fusion, in which Samus has to defeat the creature while enduring its gravity manipulation abilities.
Chronologically, Samus first encountered Nightmare in Metroid: Other M while on her journey to Sector Zero on the Bottle Ship. The creature fights Samus twice; once when she tries to enter Sector Zero, and again when she tries to exit Sector Zero. When first defeated, Nightmare's face will tear off while colliding with the walls due to the malfunctioning of its Gravity Manipulator, until the beast finally crashes to the ground. When Samus returns to the area, Nightmare will struggle to get up while making screeching noises, and the duo do battle once more. After the second battle, Nightmare will explode into pieces, leaving only the head intact with the rest of its body parts scattered. Its corpse rests on the ground until the post-credits sequence: the Galactic Federation seemingly salvages the remains of the creature during their thorough investigation of the Bottle Ship and transports the body at an undetermined time to the Biologic Space Laboratories research station.

In Metroid Fusion, Samus first encounters Nightmare in the X-Parasite infested BSL station when leaving Sector 5 for the first time, where she catches glimpses of Nightmare's silhouette flying around behind large windows (possibly part of its containment tank), causing the entire room to shake violently. It also appears when she is entering and leaving Sector 5 while obtaining the Power Bombs, though it is never mentioned by Adam after any of these encounters. After Samus obtains the Plasma Beam, Adam detects an explosion in Sector 5 and tells her to investigate. As she arrives at the entrance to the sector, Adam finally informs her of Nightmare's continued existence. Samus finds most of the arctic sector in ruins and by exploring further, she eventually finds the X-infected Nightmare in a uniquely mechanized room. It is interesting to note that the organic part of Nightmare's face appears to be deteriorated; the cause is unknown, but the decay makes the creature all the more frightening once its mask is destroyed.

The Queen Metroid is the largest and most powerful Metroid featured in Metroid II: Return of Samus, serving as the main antagonist and final boss of the game. Another Queen Metroid also appears in Metroid: Other M, battled by Samus as one of the final bosses.
She is best compared in structure to a crocodile; the creature has a quadrupedal posture with a large broad jawline containing three rows of teeth. The creature also has eight eyes in total, (two groups of four) and an extendable neck used for attacking with her impressive mandibles. Visually, the creature's features do not differ from the Omega Metroid's in any major way; only a few aspects change, such as the mouth and spinal plating. Similar to the other Metroid forms, her weak spots are her head and mouth structure as well as her stomach, the latter which can be destroyed either by one Power Bomb or some regular Bombs (not in Other M). However, her quadrupedal state also prevents external attacks on her stomach, requiring her to be destroyed from within. The Queen Metroid was the one responsible for reproducing the entire species, much like a "Queen" of an insect colony. Only very few Metroids are born with the specified genetic coding to eventually mutate into a Queen, again, much as an insect colony.

SR388
This creature thrived in the deepest confines of the entire cavern complex of SR388, in a ruined royal palace. This was the final Metroid that Samus Aran destroyed on her mission to the planet, but she took the Metroid Hatchling with her as she left.

Bottle Ship
During the events of Metroid: Other M, Metroids were cloned from fragments of the Baby on Samus' Power Suit and propagated in Sector Zero of the Bottle Ship. The first propagated Metroid matured to a Queen, something the scientists never predicted. She seems to be the organism responsible for the demise of Ridley's clone.

The Queen Metroid was stored within Room MW. When Samus tries to contact Madeline Bergman, she panics, and hits a button which opens a chamber. When Samus investigates, she sees Metroid Eggs, and learns that it would be none other than a Metroid Queen laying them.

During the battle, the Queen deploys six Adult Metroids and later grows crystalline spike plating on her head. However, she seems nearly impossible to defeat as she grows a second set of crystalline armor. Samus remembers the tragic deaths of Adam and Anthony and refuses to give up. She then loads Concentration and prepares to fire at the charging Queen, before the ship's emergency brakes throw them onto the ground. Samus takes the opportunity to shoot directly at the Queen's unprotected membrane (seemingly hitting its nuclei) and quickly enters the creature's body through its throat before laying a Power Bomb to obliterate her.

Madeline later explains that MB was the one who developed the first propagated Metroid into this beast, which treated her like its mother. They left the Queen's genetics unaltered, so she would act as a control group and produce unaltered Metroids for use.

It is revealed that Anthony Higgs (remember me?) hit the brakes on the Bottle Ship, thus saving Samus' life from the Queen.

Rhedogians are powerful creatures encountered in Metroid: Other M. They are blue in color, and possess both organic and mechanical weaponry which they will employ against enemies. Rhedogians' distinguishing features are their extendable arms, and a large set of mandibles which hang down over their faces.
Only one is met during Samus' main mission and is fought by her four times. The first encounter is alone atop the Materials Transfer Lift in the Cryosphere after fighting off seven Wave Beam-equipped Super Zebesians. The beast escapes before Samus can kill it by taking off down the Lift shaft.

The same Rhedogian reappears later in the Pyrosphere, battling Anthony Higgs and is supported by several Sovas. Samus saves him after the creature attempts to drop him into a pool of magma. Samus and Anthony sucessfully repulse the Rhedogian, but it escapes by jumping into the lava. During the battle, the Rhedogian cannot actually kill Anthony; although its attacks will occasionally hit him (signaled by his grunts), he does not receive any injuries.

The creature ambushes Samus at the top of the Desert Refinery, crashing through an elevator, while Samus is tracking the lizard-like monster that attacked her and the group at the Exam Center in Biosphere. Samus manages to repel the creature once again, and it falls down a large drop outside the arena when Samus fires a Missile as the finishing blow during the flight.

After Samus has been informed by Madeline Bergman in the Bioweapon Research Center about Sector Zero, Samus exits the center, heading for the Main Elevator. Whilst traveling through the Biosphere, Samus is again jumped by the Rhedogian. The creature succumbs to Samus' Plasma Beam and Super Missiles and is defeated once and for all, leaving the Seeker Missiles for Samus to collect.

Two different Rhedogians are later fought one after the other in the post-credits sequence as Samus returns to the station, just before reaching the Control Bridge. They can be easily destroyed with Power Bombs.