 Why does Forbes want to take Purnie?
Safe from the scrutiny of brothers and parents, there was nothing now to stop him from going to the ocean. With everything around him in a state of perfect tableau, Purnie hurried toward the ocean. He chose to ignore the negative maxim that "small children who stop time without an adult being present, may not live to regret it." With it under his arm he bounded along a dozen more steps, then stopped abruptly in his tracks. Further down the beach was a pair of two-legged animals poised in mid-step, facing the spot where Purnie now stood. It was time itself that Purnie had stopped, not the world around him. He scampered around the rockpile and down the sandy cliff to meet the tripons who, to him, had just come to life. The tripon thought Purnie's feat was superb. Purnie ran from pillar to post, trying to see and do everything at once. And tell me, Forbes, just what the hell are you going to do with them—mount them on the wall of your den back in San Diego?" Sure, it's your money that put us here; it's your expedition all the way. As Purnie followed along, a leg shot out at him and missed. Purnie shrieked with joy at this new frolic and promptly stood on his head. The sooner we get Mr. Forbes's pennant raised and his claim staked out, the sooner we can take time to look around. "There is, there is.
 Forbes wants Purnie because he emits radiation.
 Forbes wants Purnie because he emits radiation.  Forbes wants Purnie because he is very strong.  Forbes wants Purnie because he can stop time.  Forbes wants Purnie because he looks like a kangaroo.