Hint: They called him Gonzo

What novel begins with the following paragraph:

“We were somewhere around Barstow on the edge of the desert when the drugs began to take hold. I remember saying something like ‘I feel a bit lightheaded; maybe you should drive… .’ And suddenly there was a terrible roar all around us and the sky was full of what looked like huge bats, all swooping and screeching and diving around the car, which was going about a hundred miles an hour with the top down to Las Vegas. And a voice was screaming: ‘Holy Jesus! What are these goddamn animals?’ ”