It's approximate measurements are:
Length: four inches
Height: two and one quarter inches
Bowl, outer: one and three quarter inches
Bowl, inner: seven eighths of one inch
Weight: two ounces

The smallest of the 2008 Monstrosities is Urchin. Not unlike the evil chihuahuas that swarmed over lower North America in the early 1600s, Urchin is a small bundle of not nice. Rubbing Urchin's flat back seems to calm it, however, once you begin, it is best not to stop until you are completely sure Urchin is asleep.

Urchin's stem is maimed vulcanite, and it comes with a cage fashioned of a small glass mason jar with wire mesh top and corn cob bedding.