But you don't never take no care. You do bad things.
He's gonna leave ya, crazy bastard
George had constantly reminded Lennie that if he ever did something bad, to "hide in the brush" near where they went camping in Chapter 1. So, after Lennie kills Curley's wife, he runs away to this spot.
While Lennie is waiting for George to come find him, he sees his Aunt Clara. Her phyisical appearance is the same as when she was alive, but she speaks in Lennie's voice. She yells at him for causing trouble and reminds him of what a burden he is.
Next, Lennie has a hallucination of a gigantic rabbit. All throughout the text Lennie has loved rabbits and wants to tend to them in their future house. The rabbit is angry and tells Lennie that he is not responsible enough to take care of rabbits which upsets him.
George finds Lennie and makes peace with him. He assures Lennie that he has never been mad at him and this makes Lennie happy.
No, I want you to stay here with me
George tells Lennie to look across the river and imagine the land they are going to buy.
Then George shoots Lennie in the back of the head to save him from a more cruel death by Curley.