Aliens

The Aliens are toy aliens with three eyes who appear in Toy Story, Toy Story 2 and Toy Story 3.

Toy Story
In the first film, the aliens are found in a a claw vending machine at Pizza Planet that Buzz Lightyear climbs into. They believe the crane is a kind of deity who sometimes selects one of their kind to go to a better place.

One alien in particular was picked up by Sid, which then put Buzz Lightyear in view. Sid then went after him. Woody tried to escape the machine with Buzz, but the aliens pushed then back out, not wanting to upset The Claw. Sid then went home with Woody, Buzz, and the Alien. Once inside, Scud immediately greeted him, and Sid gave him the Alien to chew on, as Woody and Buzz watched in horror.

Later, when all Sid's toys were surrounding Sid, the alien (now looking more damaged) revealed himself from under Scud's feeding bowl to show it was also alive to join the rest of Sid's abused toys to teach him a lesson.

Toy Story 2
In the second film, Andy's toys (who were on a mission to rescue Woody) encounter three toy aliens inside a Pizza Planet delivery truck that they hijack to chase Al to the airport. Originally from the Crane Game inside Pizza Planet, they now serve as a car decoration. During the chase, the aliens fly out of the window, but Mr. Potato Head saves them by pulling them back in, and the aliens become quite attached to him. After the toys return home, Mrs. Potato Head chooses to adopt the three aliens as her children, much to his dismay.

Toy Story 3
In Toy Story 3, the Aliens are first seen in Andy's realistic play scenario, serving as evil accomplices of One-Eyed Bart (Mr. Potato Head's character) and Betty (Mrs. Potato Head's character), providing transportation for their escape by a pink corvette. The corvette is sliced in half by Buzz Lightyear's laser, and One-Eyed Bart protects himself, his wife, and the Aliens by summoning his "Attack Dog With a Built-In Force Field" (Slinky's role). The villains are warped to Evil Dr. Porkchop's spaceship.

Several years after the events of the previous film, the Aliens still say their message of gratefulness to Mr. Potato Head, much to his annoyance. A little later, they join the rest of Andy's toys at Sunnyside Daycare. There, the aliens meet a construction vehicle toy with a claw on it, making the aliens recite their catchphrase "The Claw" and follow the vehicle. When the toys experience a rough playtime with the toddlers in the Caterpillar Room, the aliens are being sat on and bounced on by one toddler, and they end up becoming tangled up in Slinky's coils.

Much later, as the toys make their way toward the garbage chute (the only escape route from Sunnyside that Woody has learned from Chatter Telephone), Woody, Bullseye, and the Aliens riding on Bullseye are forced to make a detour due to an approaching security truck. As they make a detour, they encounter Big Baby sitting on a swing, watching the night sky. As they sneak past Big Baby, one Alien falls off Bullseye, landing with a squeaking sound, which attracts Big Baby's attention. However, at the last moment, Woody, Bullseye, and the Aliens dive underneath a plastic bucket by the time Big Baby reaches the place where they have been hiding. While escaping on top of the dumpster, one of the Aliens gets his feet stuck, and as Woody goes back to free the alien, Lotso (who has been thrown into the dumpster by Big Baby) reaches out and pulls him into the dumpster just as a garbage truck arrives to pour the contents of the dumpster into the truck. The rest of the toys go to help Woody, only to end up inside the truck. When they are dumped at Tri-County Landfill, the aliens spot "The Claw" (a crane) and run toward it (despite Woody and Mrs. Potato Head yelling at them to come back), but are plowed away by a bulldozer and presumed dead. However they eventually manage to make their way into the control room, where they operate "The Claw" that rescues the toys, who are about to be incinerated, at the last moment. As the aliens approach the Potato Heads, Mrs. Potato Head tells them, "You saved our lives." Mr. Potato Head, to whom the Aliens' life debt they owe him in the second film have been repaid, immediately follows by telling them, "And we are eternally grateful," and he gives them a big hug as he finally accepts them as his children, implying that his attitude toward the Aliens has changed for the better. At the end of the film, they are given to Bonnie Anderson, along with the rest of the toys; when Andy shows Bonnie the Aliens, he mentions Pizza Planet as the strange alien world where they have come from.

In the end credits, they are seen being juggled by Totoro, to the amusement of their "adoptive parents." Later, one of the aliens plays Juliet with Mr. Pricklepants playing Romeo in their rendition of Shakespeare's Romeo and Juliet. Finally, the aliens are among an audience of toys who enjoy watching Buzz and Jessie perform a paso doble to "Hay Un Amigo En Mi", the Spanish version of "You've Got a Friend in Me".

Buzz Lightyear of Star Command
The Aliens are also characters in the series Buzz Lightyear of Star Command working for Star Command as scientists. It was in this series that they were first identified as L.G.M.s, short for "Little Green Men". They played an important role in the direct-to-video pilot The Adventure Begins where they were kidnapped by Emperor Zurg, who was attempting to discover the secret of the L.G.M.'s telepathic link so he could use it for his own evil purposes. It is revealed on their home planet that this power comes from the Uni-Mind: a giant orb that binds together all the L.G.M.s mentally and emotionally into a single whole. Zurg later steals and corrupts the Uni-Mind into pure evil and attaches it to a giant ray gun to take over the minds of everyone in the universe.

It should be pointed out how this series implies that the Aliens exist in the Buzz Lightyear universe, despite the fact that in Toy Story they seem to be only available at Pizza Planet. Possibly, the Aliens' toys are meant to be only sold at Pizza Planet as an exclusive tie-in deal with the cartoon.

In this series, they are voiced by Patrick Warburton.

Toy Description
From Official Website:

"Often heard exclaiming "ooohh!" in unison, the three green, multi-eyed squeak-toy Aliens now revere their adoptive parents, the Potato Heads, instead of the Claw - because Mr. Potato Head saved their lives, and they are eternally grateful."

Trivia

 * At one point while making the original Toy Story, the characters in the claw machine would have been plastic pizza slices with sunglasses instead of aliens.
 * In Toy Story 2: The Video Game the aliens are also sold at Al's Toy Barn, and their box names them Mr. Martian. A Mothership also lost a few of these aliens, which it needs to return home.
 * The line "Use the wand of power" may be a nod to the line "Use the force" from Star Wars.