The elephant's trump

Aliens are coming... to get up your nose! They don't want our oil. They don't want our water. They don't want our Brussels sprouts. (Actually, neither do we.) They just want our snot! Ugh! Who did that? Jack, Oscar, Ruby and their robotic dog Snivel have defeated one of the GUNK aliens - but there are still three more to be captured. And that's bad news when the alien you're looking for likes nothing more than the smell of farts...