cavesalamander said:
The analogy that springs immediately to my mind when I read this rules-change is Buecephalus from the Adventures of Baron Munchausen. Remember when they're in the belly of the whale-monster and the horse comes crashing through the walls to save them?
A friend of mine also compared it to Comet, from The Adventures of Brisco County, Jr.
How about Miracle from History of the World, Pt I?