What delusion does Lennie experience as he is waiting for George? Why does he remember this experience in Of Mice and Men?

Lennie sees two different items, well one actually
transforms into the other. He sees his Aunt Clara and he sees a human-sized
bunny.

I think he sees the Aunt because she represents
morality to Lennie. He knows he has done something wrong and the ethos in him is
triggered. The rabbit to me represents the passion of his or that which makes him happy:
soft things, and the hope of livin' off the fatta the lan' one day
with George.

Without George to direct his thoughts after
this severe event, I think his brain's strongest thought processes took
over.