Crocomire

The Crocomire (クロコマイヤー Kurokomaiyā) is a miniboss in Super Metroid. It is found in Norfair on the way to finding the Grapple Beam. The Crocomire cannot be killed by conventional means.

Characteristics
Samus's weapons, such as Missiles, Super Missiles, and the Charge Beam shot into the mouth only succeed in making the beast take several steps backward, depending on the power of the weapon. When not being attacked, it sluggishly lumbers forward. Curiously, if a Power Bomb is used against it, the Crocomire will become enraged and charge forward much further compared to when it is not under attack.

Behind the Crocomire lies a thin bridge covering a pool of superheated lava. Behind Samus lies a wall of Spikes. Thus, the battle is sort of a shoving match between Samus and the Crocomire: the former's goal is to push the large creature onto the bridge while the latter attempts to push Samus onto the wall of Spikes with its body. The beast periodically shoots fireballs from its mouth and will try to rake her with its claws; its projectiles can be destroyed for health and missiles. If Samus is repeatedly unsuccessful at preventing the creature from advancing, it will eventually and suddenly sprint to tackle Samus against the hazardous wall with its body, causing considerable damage. It will afterward take a few steps back before sprinting again.

When Samus manages to push the Crocomire onto the thin bridge, it will collapse under its weight, thus making the beast fall into the superheated lava. The creature will rise and sink in the substance erratically, roaring in pain as its flesh melts off its bones. Eventually, it sinks out of sight, giving a false sense that the battle is over - yet the room's doors remain locked and Samus can observe a trail of bubbles from the lava below traveling away to the other side of the chamber. When she reaches the wall of spikes, the screen rumbles for a brief moment, and the Crocomire's skeleton rips through the wall. However, due to the fact that it is now only a pile of bones, it quickly falls apart in front of Samus with a humorous noise. Its skull will remain on the floor for the rest of her mission on Zebes.

Once Samus obtains the Grapple Beam, she can come back to this room to swing over the superheated lava to receive an Energy Tank and return unharmed, contrary to using the Speed Booster and/or Shinespark method. This Energy tank can also be obtained by simply walking through the lava and taking damage, then wall jumping up the ledge.

Super Metroid
There is an unused creature in Super Metroid, known as a Stoke, that resembles a miniature Crocomire.

Metroid: Zero Mission
The Crocomire was originally going to be a boss in the prequel Metroid: Zero Mission, presumably for Norfair but was cut for unknown reasons. Its sprite can still be accessed by hacking the GBA ROM, but the existing animations are seemingly unfinished and there's no death sequence for the creature. Unlike in Super Metroid, this Crocomire's coloration was less vibrant. Also notable is that it does not have its signature rough, rugged skin, indicating that the creature was meant to be scarred in this game for its "future" SNES appearance. A fan-made IPS patch has been released that transforms Crocomire into a working boss. 

Metroid Prime 3: Corruption
There is concept art for Metroid Prime 3: Corruption created by Sammy Hall which consists of various creature designs based on the Crocomire. This 3D appearance was seemingly cut, as there is no enemy in the released game that resembles the boss.

Super Metroid manual
"This huge creature has sticky skin and spits plasma balls. When adventurers attempt to fight the Crocomire, it becomes angrier with every blow."

Super Metroid Players' Guide
"The huge and horrible Crocomire is a major obstacle in your path yet he's not even the main guardian of this section! In fact, this enormous red reptilian is so powerful you simply can't destroy him, even with a full compliment of power-ups and weapons. Your only hope is to drive him back onto the flimsy bridge to the right of his domain. Being such a bulbous creature, the bridge will crumble under him, causing him to fall into the lava pit underneath. No-one, not even Crocomire, can survive. Like Kraid, Croc's only vulnerable point is inside his mouth. You'll have to keep firing rockets and charge blasts (normal shots have no effect), otherwise he'll advance and eventually force you to your death on the spikes protruding from the wall on the far left."

Interview
Interviewer: Huh? Made it dirty?

Mashimo: Apparently, the characters I drew were fairly cute. Characters like Crocomire were so charming that when they were killed, the player would feel sad about them.

Osawa: He wanted to them to look like Fujiko Fujio's work! Then Yamane came into the picture.

Mashimo: When that happened, the characters became harsher so that the player could defeat them.

Osawa: Fujiko Fujio became Hino Hideshi!* (Laughs)

* Fujiko Fujio was the two-person manga team behind Doraemon. Hino Hideshi is a famous horror manga artist. 

Trivia

 * Crocomire is the only boss in Super Metroid that reacts aggressively when a Power Bomb is used against it.
 * No matter what attack is used, the first hit against Crocomire will only push him back a very small distance.
 * Curiously, while Crocomire is indeed fought in Norfair, it does not seem to be at all adapted to the environment; the creature is inside an unheated room and the lava which it falls into destroys its skin, pointing to the fact it cannot tolerate any form of heat. Why Crocomire was in the unsuitable and mostly heated Norfair region is unknown. However, it should be noted that the lava present in the chamber is more intense than the lava seen everywhere else in Upper Norfair; this superheated lava is commonly found only in Lower Norfair, therefore insinuating that Crocomire was possibly adapted to Upper Norfair's more common lava and heated regions. It is also still able to damage the Gravity Suit.
 * In the second Castlevania title for the Game Boy Advance, Harmony of Dissonance, the player will eventually come to an area called the "Skeleton Cave". In it, there are giant skulls resembling Crocomire's which can be used as ramps to get to the next part of the area. Since Super Metroid paved the way for many future 2D Castlevania games from Symphony onward, this game appears to pay a specific homage to the franchise.
 * If Samus uses the Grappling Beam via the Spacetime Beam and grapples Crocomire, it will be able to be pulled around with disembodied legs and arms. Its tongue should stay in place, flopping around.
 * If the Hyper Beam is obtained ahead of time via hacking, or by using the charged Plasma Beam and (after Crocomire has already been hit once.) fired into the Crocomire's mouth, it will do so much damage to it that the Crocomire will dash straight into the lava after only a single shot.
 * Curiously, when the Crocomire's skeleton falls apart, the sound it makes is similar to that of a Dry Bones from Nintendo's Super Mario series. Dry Bowser is a form of the series' main villain and a derivative of the Dry Bones species concept. Dry Bowser first appears after the player drops Bowser into a pit of lava (in the classic style of the series); first Bowser rears up out of the lava to roar at Mario, then disappears. Dry Bowser then does the same. Like this brief appearance by the Crocomire, Dry Bones (and therefore Dry Bowser) are also living skeletal creatures. Whether Crocomire or Dry Bones influenced the other or not is unknown.
 * Crocomire's skeleton seems to lose one pair of lower legs.
 * Crocomire and Spore Spawn are the only bosses in Super Metroid to leave behind remains after their death. In Crocomire's case, it is his skeleton. Kraid and Draygon are two other bosses who leave behind their bodies, but both quickly sink into the ground.
 * Vorash in Metroid: Other M is facially similar to Crocomire.
 * The name Crocomire is a portmanteau of the two words "crocodile" and "mire".
 * The boss battles with the Omega Metroid in Metroid Fusion, the Kiru Giru in Metroid: Zero Mission and the Desbrachians in Metroid: Other M involve Samus firing at them to push them back, similar to Crocomire.
 * The Super Metroid manga has a strip called Looks Happy, Looks Sad, where Samus jumps onto Crocomire's head and counts its eyes, overjoyed that all eight are completely round. Samus does not notice that the embarrassed Crocomire is crushing her with the Spikes on the wall.
 * Donkey Kong Country Returns, created by the studio behind the Metroid Prime Trilogy, has what appears to be Crocomire's skull in the background of the Foggy Fumes level.
 * Crocomire's roar is similar to that of Titanosaurus, a monster from the Godzilla series.
 * Crocomire does not attack Samus unless she runs to the right in its room.
 * If Samus travels back to the room, Crocomire's skull will have moved significantly to the left from where it fell, so that its bottom jaw is no longer visible (hidden by foreground bushes), and its spine now visible. Furthermore, the skull will slightly move up or down when coming on/going off screen to the left as Samus moves. Why either of these happens is unknown.
 * There appears to be a row of breakable blocks above Crocomire's room that can be heard breaking if fired at with the Wave Beam equipped. Their purpose is unknown.

Gallery
Crocomire Крокомайр