(Mental Floss) -- Watching the post parade at this weekend's Kentucky Derby will surely fill some of our heads with dreams of horse ownership.
How did the julep-sipping folks acquire their prized horses? How much is buying a racehorse going to set you back? Are they sound investments?
These are all tricky questions, but let's take a look at a few stories of horse sales that turned out to be winning lottery tickets...and a few that were more dud than stud.
Mr. Prospector becomes a daddy again and again
In 1971, Mr. Prospector was a yearling that fetched $200,000 at auction. When he took to the track, he was good but not great; he won seven of 14 starts but only brought home $112,170 during his career.
Still, in 1980 he sold for $20 million.
What happened? It turns out "Mr. P." was a stud in every sense of the word. While his racing career might not have been the most distinguished, it's tough to argue with his results as a stud.
He sired a winner of each of the Triple Crown races, and his grandchildren and great-grandchildren have been similarly speedy. His sons, grandsons, and great-grandsons have combined to win over 30 Triple Crown races and pull in around $100 million in earnings.
Mr. P.'s Derby-winning son Fusaichi Pegasus fetched $60 million in 2000, and 18 years earlier, another son -- Belmont winner Conquistador Cielo -- sold for $36.4 million.
John Henry drives steel, wins cash
When John Henry, a yearling foaled in 1975, came up for bids at the Keeneland January Mixed Sale, he didn't generate much buzz. He had fairly mundane bloodlines, he wasn't particularly big, and he had a nasty temper -- he got his name from a tendency of smashing steel feed buckets.
John Calloway bought the unheralded gelding for a modest $1,100 investment and hoped he could make a little cash back on the horse.
How did it work out? By the time John Henry retired from racing, he was the top-earning gelding in history with over $6.5 million in career earnings. He won 25 graded stakes races and was racehorse of the decade for the 1980s. Not a shabby return on a $1,100 investment.
The Green Monkey makes a monkey out of bidders
Unless you're a huge fan of the band America, you might not envision shelling out eight figures for a horse with no name. That's exactly what happened in a January 2006 auction at Calder Race Course, though.
When the auctioneers brought a colt who was only known as "number 153" to the auction block, a fierce bidding war broke out. Buyers weren't afraid to open their wallets for a colt that was described as "perfect," and when the hammer dropped the horse went for a record $16 million.
The winning bidders quickly christened the colt The Green Monkey, and excitement to see how the horse would do in races began to build. After all, the colt had run an eighth of a mile in a blazing 9.8 seconds in pre-auction workouts, so anything was possible once he started racing.
The buyers thought they were getting a Triple Crown threat. Instead they got the thoroughbred version of Ryan Leaf. The Green Monkey could never translate his workout speed into actual races, and in his career, he only managed one third-place finish in a measly three starts.
In 2008, his owners retired him from racing to stand at stud. If his progeny enjoy the success that eluded the Green Monkey, he might make some of his substantial purchase price back. It will be tough, though; right now he only pulls in $5,000 as a stud fee.
...But he's in good company
The Green Monkey shouldn't feel too bad. The horses he took the "most expensive colt" record from didn't fare much better.
Seattle Dancer set the yearling price record in 1985 when he went for a cool $13.1 million before going on to win $150,000 in his five career starts. Snaafi Dancer's sale in 1983 was the worst investment this side of Pets.com stock; the first yearling to break the $10 million price mark never raced -- and was infertile.
Cigar comes up empty
Even casual sports fans may remember Cigar, the bay stallion who racked up an incredible 16 straight wins from 1994 to 1996. If Cigar had picked up just $187 more during his career, he would have become the first horse ever to break $10 million in race earnings.
When the former Breeders' Cup Classic Champ came up for sale in 1998, there were more than a few breeders who wanted to get their hands on him.
Cigar sold for $25 million and promptly went out to stud to recoup some of that cash. That's when breeders discovered a problem: the horse that some analysts called "the second-best racehorse ever" was infertile.
Cigar's new owners got a record $25 million payout on an insurance policy that covered infertility, and the champion stallion is spending the autumn of his years at the Kentucky Horse Park's Hall of Champions.