Kraid

Kraid is a fictional alien monster from the Metroid video game series, resembling the Japanese monster Kaiju. With a fat, bloated reptilian appearance Kraid is one of the biggest as well as largest monsters that Samus Aran encounters. He appears as one of the two minibosses that appear in the NES/Famicom Disk System original Metroid, the other being Ridley. Kraid's main attacks are firing spikes from its belly as well as spinning claws from his fingertips.

Profile
Almost nothing is completely known about Kraid himself. Whereas Ridley would be considered highly intelligent, no data has been given regarding Kraid's mental abilities. Fan work often depicts Kraid being the lesser intelligent of the two. The Space Pirates often use Kraid as a guardian to defend items or locations of significance with his intimidating size, impregnable hide as well as his ability to fire countless organic projectiles, he fulfills this role well.

Metroid
In Metroid, Kraid is the boss of Kraid's Lair, or simply Kraid. Due to the lack of colors and the sprite's limited sizes, the artist's interpretation of Kraid for the game's artwork differed considerably from what the game designers had in mind. Kraid's artwork clearly shows that in addition to its smaller size in this game (than all its later appearances) to have its mullet of green hair to run down its back and only has two eyes compared to originally have three. Upon Kraid's defeat, Samus receives 75 missiles.

There is a decoy Kraid that Samus can encounter before terminating the real Kraid. Yet due to the fact that Kraid's Lair has multiple paths the player can take to reach the real Kraid, the player may never come in contact with the fake Kraid. This fake Kraid is similar in appearance to the real Kraid but is a darke shade of green and is rather feeble in comparison with the real Kraid, though fake Kraid will regenerate after it is destroyed and Samus returns to the same room.

Super Metroid
In this game, Kraid appears much larger than he does back in the original Metroid, taking up the space of two vertical screens. Now, Kraid is completely impervious, with exception for its mouth, in which Samus can fire missiles in after Kraid is shot in his third eye. As in the original, there is a fake Kraid in this game though dwarf-like in comparison, both in terms of size and strength. Just like the clone in Metroid, it regenerates if it is destroyed and the player returns to the same room. There is a possibility that this Kraid may be a reference to its smaller size in the original Metroid, perhaps indicating Samus merely killed a child.

Upon Kraid's defeat, Samus earns the Varia Suit upgrade.

Metroid: Zero Mission
Here, Kraid is reminiscent of its appearance in Super Metroid, retconning Kraid's size and proving that he did not grow between its appearances in Metroid and Super Metroid. Also, worthy of note that there is no Kraid decoy in this game. In the room where fake Kraid would normally be, he cannot be found. After Kraid is defeated, Samus earns the Speed Booster.