Mellows were a species of aerial insectoids indigenous to the planet Zebes, inhabiting Brinstar. Mellow have a purple-hued exoskeleton, red-tinted eyes (presumably of the compound variety), while their wings are green; these colors may indicate a warning defense to warn creatures of the danger they will face should they threaten a group of Mellow, in a similar manner to bees, hornets, and various other animals known on Earth. They are hive-oriented by nature and will attempt to defend their nests at all costs. As such, many of them will spend most of their life circling their nest when near it and chasing potential threats even when there is no known Mellow Nests in the area. Strangely, Mellow nests are built out of a substance that seems to melt with increasing damage; how this is created is unknown.
They appear to be related to the Mellas both by name as well as nature and physiology. They also share their lifestyle with the Memus found in Kraid's Lair. However, because of the obliteration of their homeplanet Zebes, they are now considered officially extinct.
- Metroid (First appearance)
- Metroid: Zero Mission
- Super Metroid
- In Metroid Zero Mission, Mellows are found in a limited area of Brinstar (about 5-6 rooms) and disappear for the rest of the game if Samus Aran destroys all of their nests, one of which is hidden behind a wall and guarding a Missile Tank.
- Mellow Nests go through three visible stages when damaged: fully healthy, where the nest is entirely intact; then becomes damaged and sags somewhat, the nest appears to be melting; eventually the nest sags even further, seeming to be entirely melted; finally the nest will degrade into the ground, melting completely.