Phantoon is a Super Metroid Boss found in the Wrecked Ship. It is a supernatural ghost entity that is intangible and invulnerable except for its single eye. It is this eye that, when open, serves as its connection to the material world and can be damaged.
Over 4 meters tall, Phantoon resembles a bulbous severed head, with it's lone eye centered in the gaping, toothy maw of it's mouth. A pair of tentacles streams out from it's jaw, one from each side of the mouth. It has downward spikes where its ears should be, and the bulk of its head (including a massive swelling forehead) is bare save for a solid ridge running up the center of its face.
The manual implies that Phantoon is the ghost of the Wrecked Ship itself, and it is tapping into Mother Brain's vicious brainwaves. It is likely that Phantoon is controlled to an extent by Mother Brain. Interestingly enough, after its defeat, the Wrecked Ship gains electric power, and Coverns stop appearing.
Phantoon's only method of attack is by creating balls of fire out of thin air and controlling them. Typically he makes the boiling balls of blue fire hop towards Samus, but he is also capable of dropping them from above or swinging them. Phantoon becomes very angry if struck with super missiles, and his retaliatory vengeance is to repeatedly swing "chains" of flame across the room.