This post is devoted to the ever changing Wampa. The wampa is Hoth's indigenous yeti-like predator species. Originally the wampa was to have had quite a bit more screen time than it wound up with. Not only was it meant to imperil Luke and kill his tauntaun, but a number of the creatures had also infiltrated the rebel base, killing more wampas (a dead one being examined by a 2-1B medical droid can still be seen in the sequence where Han is inquiring about Luke's missing status), endangering the rebels, and so forth. Attracted by R2-D2s vocalizations, the wampas are led into a room where they are locked in. A warning label is slapped on the door, which C-3PO removes as he, Han and Leia flee Imperial troops, as they make their way to the Millennium Falcon. The Imperials, no longer warned by the removed label, enter the room containing the angry, confined wampas, and are slaughtered.
The reason for the removal of this subplot, much of which had been filmed, had less to do with streamlining the story than it did with the wampa's costume proving to be not very convincing.
The bulky costume with its bug-like eyes, seen above, was probably inspired by the apt, a white, tusked, yeti-like predator with huge multi-lensed eyes, like a fly's which appeared in Edgar Rice Burroughs' John Carter of Mars series of novels. This series clearly inspired much of Star Wars, not merely in it's sprawling space adventure storytelling, or its space princesses, but in many of the names in the books, such as Jed and Jedak, Banth, and Sith. The alp, as interpreted by legendary Scinece Fiction and Fantasy artist Michael Whelan, is pictured below.
The inclusion of the wampa as a whole seems to have been a means to explain facial scarring that actor Mark Hamill suffered from a serious car accident he was in on January 11, 1977, before shooting final scenes for STAR WARS (which were landspeeder shots completed with a double). There have been a lot of stories concerning the car accident since it occurred, including some that suggest that Hamill crashed on purpose either because he couldn't handle the sudden fame, or because he knew that STAR WARS was going to be very successful and it was the only way he could get out of a contract he was locked into so he could go and shoot EMPIRE. The television series was EIGHT IS ENOUGH, and Hamill was signed to play David. When he asked to be released from his contract so he could pursue his movie career, ABC refused. His car accident left him with a smashed his nose and fractured his left cheekbone, and required extensive reconstructive plastic surgery. Unable to film "Eight is Enough," ABC was forced to recast his part with Grant Goodeve. The story has changed many times in its retelling, including details given by Hamill, who sometimes claimed he merely broke his nose, to other times referring to his face looking like hamburger and requiring skin grafts. In any case, smashing your car to get out of a contract seems like a desperate and very risky action to take, since there's no way to control the extent of how badly you'd be injured, with the possibility of being killed a likely outcome. In any case, the wampa attack was used to explain the scars now appearing on Luke Skywalker's face.
For the wampa attack itself, another costume was built, which was an improvement over the bug-eyed version, but this one proved too cumbersome for the actor inside, and was also jettisoned, though the pants portion of the costume can be seen as Luke is dragged through the snow, and portions of it were included in the movie as the wampa moved through its cave as Luke struggled to free himself.
For the actual wampa attack scene, the costume was replaced with a puppet created by Jon Berg and manipulated by Phil Tippett. The puppet is only on screen for a few seconds, but it's apparent that it has no arms.
The arm that knocks Luke off of his tauntaun, and strangles the tauntaun itself, was an elongated full arm glove, and you can actually see the jacket of the person wearing the arm in frame at the far left (as well as what looks like someone's hair a few seconds earlier.
Oddly enough this was not covered over when George Lucas tinkered with the trilogy for his special editions released in the late 1990s. What was changed (again) was the wampa costume, and the very look of the wampa itself. Instead of shots of the wampa's legs and arms as it moved through the cave, a new, better looking costume was made, and we can now see the wampa crouching down eating Luke's tauntaun before it gets up to retrieve Luke.
This wampa doesn't really look much like the puppet, which was left in, nor the discarded second costume, which also remains in quick shot of the wampa lunging at Luke before Luke chops its arm off with his lightsaber.
Why this shot wasn't reshot with the new costume is a mystery? If you're going to spend the money to build a new costume to improve a scene, then why leave in footage of a less convincing costume that looks nothing like the new one? Or brief shots of a puppet that don't match the look of the new articulate mask either?
I always liked the wampa and the tauntauns, though it is still quite a bit of screen time to devote to explaining the changed look of one of the main characters, when a briefer scene, or even a line of dialogue could have done the same. The scene has little other function to the main movie other than to demonstrate Luke's new profiency with the force as he telekinetically summons his lightsaber to him, and to introduce the snowspeeders before their big battle.
Below is how STAR WARS preproduction designer, Ralph McQuarrie, envisioned the wampa, which with the combination of those eyes and it's more human-like appearance is pretty creepy looking.