Pokemon's First Appearance: Pokemon Gold, Silver & Crystal

This half Flying, half Psychic Pokemon has a decent combination of non-damaging and damaging moves (including Hyper Beam, Solar Beam, Psychic and Fly), as well as a decent base stat total (470). Unfortunately, it's weakened by several types of attacks including Rock, Ghost, Electric, Dark and Ice. Other than that Xatu is either damaged normally by other attacks, or resistant to them.