"Well thank you for crushing my inner nine-year-old's ego." It's said in jest, and there's no heat to the statement. Banner's statement, though, makes the playfulness drop away from his presentation.

"Awesome," he says, in a tone that means anything but. "It came from a human donor. Don't even ask me why it works on a tribble." So maybe science isn't his strongest subject, but he's pretty sure that you really shouldn't be able to just crossover the species like that. He rubs a hand across his occipital bone and then down against his neck. "Do you think you can isolate it and-- I don't know, recreate it or something?"