ATAT is the crossword answer to clues like
[Giant walking combat vehicle in “Star Wars” films]
Short for “All Terrain Armored Transport,” the ATAT (usually written “AT-AT”) is the [Massive walker in “The Empire Strikes Back”].
The quadrupedal [Tank employed during the Battle of Hoth] was visually inspired by an extinct hornless rhinoceros known as Paraceratherium, which likely stood about twenty feet tall.
That’s a big RHINO [Where to see the horn of Africa?], but that’s only about a third the height of an ATAT–no wonder it’s a [Vehicle that “handles like a drunken bantha” according to Han Solo.]
However, ATAT isn’t always clued as [“Star Wars” battle craft with a reduplicative name] that’s stolen by Han SOLO [Darth Vader’s son-in-law Han ___]. When it doesn’t do a [Star turn] [Alone] as an AT-AT, ATAT is the final two-thirds of the gunfire sound that starts [Rat-___], so it can also be seen as a
[Rat follower]
[Rat chaser?]
[Rat tail?]
Occasionally, clues suggest ATAT suffices without the rat to be [Machine gunner’s syllables].
It seems likely that LUCAS [Noted filmmaker with a dog named Indiana] had [Rat-___ (Tommy gun sound)] in mind when the [The Galactic Empire’s “Imperial Walker”], but I don’t have any definitive evidence to point at, at least right now.