Well, the chick grew up into a chicken, but you’re still not sure how the egg got into that cave...

Space Chicken was aptly named for her beliefs.  She believes through and through she came from space.  According to Space Chicken she was sent to take over a world called Abidos, to take it back from all the evils that rule it.  Unfortunately she was discovered and while still in her ship she crashed into Earth.  Her ship was utterly destroyed and only small shards were left.  After years of work she has put her ship back together, and it strangely resembles a chicken egg.  Regardless of the ship being repaired she cannot complete her mission.  She grew too much and no longer fits inside the tiny compartments of the ship.  Due to this she has become overly temperamental and has sworn vengeance to the one who forced her crash landing.  Space Chicken formed an alliance with several of her other comrades who crashed into Earth over the years.  This alliance is greatly feared by most of the world's population, due to the members' seeming insanity and relentless clucking.