why does the giant rabbit appear to lennie?

Emphasizing the delusional nature of Lennie's point-of-view, Steinbeck adapts his one experimental narrative gesture in the novel, choosing to depict two hallucinations - first Aunt Clara, and then (more ludicrous still) a giant sardonic rabbit. Both aunt Clara and the rabbits are thoughts which give George some comfort but now they are twisted. It is unclear whether we are supposed to understand these hallucinations to be one-time phenomena or regularly recurring. (By the way, the reader may find it a bit unbelievable that this gentle giant, who everywhere else proves incapable of understanding figurative language, is able to imaginatively generate such colorful self-chastisements as "you ain't worth a greased jack-pin to ram you into hell" (112).)

In the 5th line do you mean Lennie instead of "George"? I didn't think George got comfort from the bunnies or Aunt Clara?