Alien

Aliens are a species of extraterrestrial beings that appears in the Banjo-Kazooie series. They are grey, have teardrop-shaped heads, large green eyes and are normally seen wearing helmets.

Banjo-Tooie
In Banjo-Tooie, four aliens, Alph, Beti and Gammo, can be found stuck in the sea next to Jolly Roger's Lagoon, as their UFO ran out of fuel. To help them, Banjo and Kazooie must shoot Ice Eggs in order to power up the crystals, consequently allowing the Aliens to leave. They reward the duo with a Jiggy as they fly away.

In Hailfire Peaks, Alph is found dead in ice. Mumbo Jumbo needs to bring him back to life with a Mumbo Pad. This Alien then asks the duo to find his missing children, Alphette, Betette and Gamette, who fell from the UFO. When they are all found, he rewards the bear and bird with another Jiggy.

Banjo-Kazooie: Nuts & Bolts
In Banjo-Kazooie: Nuts & Bolts, the Alien family can be found in the Terrarium of Terror, frozen in cryogenic capsules located in an underwater dome. One of them, however, is separated from the rest and can the found at the top of the world. While their capsules can be broken, they will still remain unconscious if this is done. Only five aliens appear, with no mention of the sixth one.

In the mission "Family Misfortunes," found in Act 3 of the aforementioned world, "B-066Y," who believes to be a distant cousin of the Aliens, asks for Banjo and Kazooie to bring the solitary alien to the underwater dome where the other Aliens are located so they can all be reunited.

Trivia

 * The names for every notable Alien found in Banjo-Tooie comes from the Greek alphabet.
 * When the Aliens in Jolly Roger's Lagoon are first interacted with in Banjo-Tooie, Kazooie asks if any of them is called "Elvis." This is a reference to the character from Perfect Dark.