Widely respected American poet Ogden Nash once wrote: "In the game of mules, there are no rules."
He was clearly thinking of horse racing and although he didn't know it at the time - he died in 1971 - he could have been referring to Mosse.
The galloping machine that made it five from five with an ears-pricked, last-to-first breeze around Ellerslie on Saturday, breaks all the rules.
Rule one broken when you look at the physicality of Mosse - and that's where it starts with a racehorse - you say, yes, he'll be a 1600m horse.
Wrong. For all that Mosse's magnificent sire O'Reilly is a wonderful begetter of classy racehorses, he leaves only a relatively small percentage of horses like himself - brilliant speedsters. Looking at him, Mosse shouldn't have the outstanding turn of foot he possesses.
Rule two: Horses on their way to group one can often make one-win and two-win rivals look ordinary as they brush past them late in a race.
But you don't do that to a horse like Durham Town.
Mosse swished past Durham Town as though he was a pit pony on Saturday on his way to winning the $70,000 group three Aussie Butcher Concorde from last on the home.
Durham Town is no pit pony, he's one of the finest sprinters we have.
Rule three broken - you don't offer up the audacity to prick your ears while you're doing that.
Everyone wants to ask one question - how good could Mosse eventually be, given that our best horses here can't get him out of his comfort zone and the fact that, in terms of development, he's still a big baby?
Part-owner and trainer John Bell doesn't even want to think about that.
He knows he's in an industry where those who get too far ahead of themselves end up with patches in their jeans.
Wisely, Bell is simply enjoying the moment, revelling in the now.
But he's still inclined to occasionally shake his head. "It makes the hair stand up on the back of your neck when you see that stride."
Every rival on Saturday had a close look at the stride as Mosse dashed through the field from last at the 400m.
If you think Mosse's performance was group one, so was the effort of rider Jason Waddell.
Bell told Waddell when he legged him on before the Concorde: "The boxes are all ticked, go out there and enjoy yourself."
Waddell did enjoy it - Bell hated it.
"For 90 per cent of the race I was terrified. When George Simon said: 'The favourite is stone motherless last on the home bend', I was not in good shape.
"It wasn't until I saw him start to gather Durham Town in that I released some of the stress."
Waddell currently has racing's coolest head out on the track.
Most wouldn't even imagine the white-hot pressure on Waddell when the talented sprint field turned into the straight all in front of Mosse.
He had a lightning decision to make - hook wide for a clear run, but at the risk of the inexperienced Mosse getting "lost", or charge through the pack and hope the gaps came.
Waddell didn't hesitate going for the latter and at no stage did he panic when things got tight on two occasions.
It was a brilliant ride under difficult circumstances.
Mosse has a way of endearing himself to all around him.
Former jockey Brent Doyle, who rides the horse in most of his work, wasn't a total believer to start with.
When Bell asked Doyle one morning what he thought of Mosse, Doyle said: "Catering King is the best horse I've ridden, he was a V8".
Bell picks up the story: "After a gallop one more recent morning, Doylie came in and said: 'I was wrong, John, this thing's a V12'."
For all of the size of the motor, Mosse is a gentle giant at home. "He just waddles around the place," says Bell.
"But take him to the track and put a saddle and a rider on him and you have to lead him out.
"He knows what he's there for when it matters." And the opposition saw it clearly on Saturday.
Further south, Final Touch's $200,000 Westbury Stud Captain Cook Stakes win at Trentham came at the right time.
North Canterbury co-trainer Karen Parsons says she and her husband, John, are about to give racing away.
John Parsons has been almost totally blind in one eye for seven years and a year ago the other eye began deteriorating.
"It's a type of bleeding behind the eye," said Karen Parsons, "and they've been injecting the eye for 12 months, but with only partial results.
"It's been a major battle for us and to be fair it's only this mare [Final Touch] that keeps John going. We are all bar finished."