Frigate Orpheon is a stage in Super Smash Bros. Brawl that takes place in the beginning of Metroid Prime, and in the background you'll see the Parasite Queen, who will not attack. After fighting for a bit, the lights will go off, making the battle more intense than ever. Eventually, the whole stage will flip 180 degrees and you'll have to fight on the opposite side. You will not get hurt when you flip, but you may get K.O.ed.
This particular stage is featured on a Space Pirate frigate that was ambushed by an evil, mutated Parasite Queen. Ironically, the Space Pirates constructed using Phazon in high hopes that they would be able to use the material against their enemies, but this particular station ended up being destroyed because of it. In the background, the Queen will stay put in her container, never harming the players on the course as she would in Metroid Prime.
The Parasite Queen was introduced in Metroid Prime where she was killed off pretty quickly by none other than Samus Aran. It's a mutated creature that was a result of Phazon testing by the Space Pirates, and she'll be the boss of the first level. She attacked by spraying acid at Samus, though the bounty hunter could dodge this by shifting either left or right and then attacking her with all she had.