Donativum has gone from "complete menace" to Breeders' Cup contender.
John Gosden's son of Cadeaux Genereux bids for Stateside glory in Saturday night's Juvenile Turf at Santa Anita.
But that eventuality looked pretty unlikely when he first joined the Newmarket handler.
Gosden admitted: "He was incredibly unruly when we brought him in and spent most of January and February on his hind legs. He was a complete menace."
Donativum failed to win any of his first three starts, culminating in a seventh-placed finish behind Flashmans Papers at Royal Ascot in June.
It was then that Gosden decided the colt should be gelded, and the rest is history.
"After that, I decided that enough was enough, we're not going to make a stallion here. We gelded him and he's been a pleasure to be around."
The decision brought immediate dividends for Gosden and connections, with Donativum winning his maiden at Yarmouth.
And then on his last start he scored in the Tattersalls Timeform Million at Newmarket earlier this month.
Now Gosden can happily watch his reformed character enjoy the Santa Anita sunshine as he prepares for the biggest test of his career so far.
"He won that race and he paid for his ticket out here. He's enjoying the California sun out on the track this morning happy."
Frankie Dettori will take the mount on Saturday night, and Donativum is as short as 11-2 for the big race.