"One-Arm" was the appellation given to the female wampa that Luke Skywalker encountered in the ice cave on Hoth in 3 ABY.
A female wampa resided in the ice cave on her native world Hoth in which Luke Skywalker was taken to after being attacked whilst mounted atop a tauntaun by a male wampa. When Skywalker awoke, he was dangling from the ceiling of the cave. Attempting to gain his bearings, Luke surveyed the cave and noticed the wampa was eating the remains of a tauntaun. Luke used the Force to pull his lightsaber from the ice and cut himself free, and escaped with a facial scar and bruises. In the process, the wampa lost her arm when Skywalker used his weapon to fend it off.
The wampa later became head of a band of other wampas, organizing them into a group capable of attacking the hunters who arrived on the world. They even devised how to stealthily break into Echo Base. When Skywalker returned to Hoth in 12 ABY with Callista Ming, the wampa recognized him, and tried to kill him again. The wampa was slain by Luke in the battle.