- “You idiots! You...You fools! Oh, you imbeciles!”
- ―Cruella to Jasper and Horace
Jasper enjoys drinking alcohol, playing darts and watching What's My Crime? with Horace. He is the taller of the two.
Horace is shorter, fatter and loves sandwiches and cakes. They are hired to dognap Pongo and Perdita's 15 Dalmatian Puppies to be used in making Cruella's fur coat. Neither one seems to be very intelligent, but Horace appears to have more insight and is often shown to correctly guess what the Dalmatians' plans are. Jasper, however, quickly rejects these ideas in favor of his own believing that dogs couldn't possibly be that intelligent despite already showing that they indeed are. Although Jasper and Horace carry out Cruella's deeds, they do not enjoy it and do it only for money.
In the sequel, they finally stands up for themselves, reform, get pardoned for their part in kidnapping the puppies and open up a clothes corporation.
In 101 Dalmatians, they sneak into Roger and Anita's house, by attempting to pass themselves as repairmen from the Electric Company (Kanine Krunchies deliverymen in the sequel and the musical version.) Nanny refuses to let them in since Roger and Anita are gone but they force themselves in, and Jasper toys with Nanny up in the attic, while Horace steals the puppies, and they transport them to Cruella's former home, Hell Hall. Soon after, the dognapping is covered by the newspapers, causing them to attempt to back out. They call Cruella and ask for their payment, but she refuses to pay until the job is done.
At Hell Hall, they laze about watching and eating, along with the stolen puppies and 84 bought puppies. This is where their potential kindness comes into play, as they allow them to watch but tell Lucky to move so they can see "What's My Crime?". Eventually, an incensed Cruella arrives and tells Jasper and Horace that she "wants the job done first thing in the morning," or she'll report them to the police. Though Jasper notes that the puppies were not big enough for the amount of coats Cruella apparently desires, she decides to settle for what they can get and leaves. While they are watching the show What's My Crime?, the puppies are rescued by Sergeant Tibbs. After the show has ended, Jasper and Horace argue over whether or not Jasper skins and Horace kills them and vice-versa but are taken off track of arguing when they overhear a sound from the door.
Jasper and Horace then notice that the puppies have escaped, and begin a search of the house. Eventually, they are able to corner the puppies in a room. Before they can kill them, Pongo and Perdita arrive and fight Jasper and Horace. While the puppies escape, Horace is tripped into the fireplace by Perdita and Jasper gets his pants pulled down by Pongo. Both are buried underneath the ceiling when it collapses.
After escaping the debris, they track the Dalmatians to a farm building via their footprints. After being attacked by Captain, they realize that the dogs have already left the building. They attempt to head off the dogs, but the Dalmatians elude them by traveling up a frozen river.
A few days later, Jasper and Horace meet with Cruella on the road. Though they attempt to quit, she forces them to continue. She points out that the footprints lead to a nearby village called Dinsford. There, Jasper and Horace search for the puppies. Horace points out some "Labradors", suggesting the possibility that the dogs disguised themselves by rolling in soot. Jasper blows off the idea and calls Horace an idiot before smacking him in the head.
When the Dalmatians are discovered to be hiding in a moving van heading for London, they pursue it in their truck. Jasper makes a plan to ram the van into a ravine, but Horace gets scared and pulls out the steering wheel causing the truck to slide down the mountain off aim and ends up hitting Cruella's car. She suffers a breakdown, cursing their incompetence while they just sit there sulking, but Jasper simply tells her to shut up finally getting the courage to stand up for themselves.
It can be presumed that they and Cruella are later imprisoned, although the film does not show what happens to them.
In the live-action remake produced by John Hughes, Jasper and Horace were portrayed by Hugh Laurie and Mark Williams. They were inspired from Harry Lyme and Marv Murchens from the first two films of the Home Alone franchise (which were incidentally produced by the same producer). Here they are both skinny (though Jasper is still thinner than Horace) and aren't implied to be related. They are still very similar to their animated counterparts, though they are depicted as much more ruthless characters, and never reform. Jasper is also shown to be a little bit smarter. They actually seem to enjoy animal cruelty (or at least, Jasper does), even deciding to take over taxidermist Mr. Skinner's job of killing and skinning the puppies (in this version, their job initially is just to kidnap them). They also appear to be more polite to their boss, never once bad-mouthing Cruella. At the end, tired of all the misfortunes they had endured after kidnapping the puppies and accidentally letting them escape, they allow themselves to be arrested and end up being sprayed by a skunk that Cruella unknowingly brought with her, causing them to scream in terror and cover their noses.
Unlike their counterparts in the animated version, Jasper and Horace aren't seen in the sequel, 102 Dalmatians, which assumes that they may be still in prison.
In 101 Dalmatians: The Series, they are the "H. and J. Concepts" company and are employed by Cruella to do her dirty work. This involves delivering ransom notes and going through Anita's trash. Unlike the movies, they have American accents and dressed differently than they did before (due to the series being set in America).
In 101 Dalmatians II: Patch's London Adventure, Jasper and Horace are the tertiary antagonists. Cruella pays their bail money so that they can round up the puppies for her artist friend Lars to use as canvases. They passed themselves as Kanine Krunchies deliverymen, and have succeeded into luring the puppies into the truck. They also had Nanny tied up in a well. However, when Lars refuses to kill the puppies, Cruella decides to finally get her spotted fur coat. After she, Jasper, Horace, and Lil' Lightning (Thunderbolt's envious sidekick) are thrown into a river, they're arrested; however, Jasper and Horace are turned loose after they, finally having had enough of Cruella, confessed to Nanny, Roger, and Anita that it was she who told them to get the puppies and is behind the dognapping. After they are both pardoned, they apparently go straight and obtain their own line of sundresses.
Jasper and Horace are both some of the villains imprisoned on the Isle of the Lost. Jasper now has a son named Jason or Jace and Horace has a son named Harold or Harry who are accomplices of Cruella's son, Carlos.
Jasper and Horace make a cameo in the Bonkers episode "The 29th Page" at a prison line-up.
Jasper and Horace also made a brief appearance in the cartoon The Saga of Windwagon Smith.
Jasper and Horace make a small amount of appearances in merchandise for the park and a few live appearances. Most of the merchandise including them have to do with Disney Villains although they have been in some Disney Cruise Line material.
On Main Street, U.S.A., Jasper and Horace are forced to work for Cruella in an attempt to find the Crystal of the Magic Kingdom as she threatened to murder them if they refuse to follow her demands. Upon learning that Pongo has contacted the local dogs to help guard the crystal, she sends Jasper and Horace to capture and eliminate them. Jasper creates several traps to capture them and Horace takes them to Cruella's lair. When the park guests arrive, they defeat Jasper by trapping him in one of the dog traps. They then head to the lair, where Cruella orders Horace to eliminate the captured dogs. Before he can, the guests arrive and unleash them. They then attack Horace, giving the guests a chance to go after Cruella.
In the former Walt Disney Studios Park parade, both Jasper and Horace were seen during the Dalmatians' unit with a large sack, ready to kidnap the puppies. They seem to be based on their "Live-Action" occupation.
- The fact that they share the same last name implies they are brothers (who at least share the same father). The sequel proves that they're full-siblings when it's mentioned that they also have the same mother. According to Sorcerers of the Magic Kingdom, they also have a cousin named Bob.
- This may be a refer back to the film where they were talking about the task Cruella had given them. Horace had explained the plan, following with "..and Bob's your uncle," an English saying for a completed task.
- In the original novel, they were named Jasper and Saul. For some reason, Saul was renamed Horace, although it was never stated why this happened.
- Hugh Laurie and Mark Williams were reunited in a film adaptation of The Borrowers in which Hugh (Jasper) played a policeman named Officer Steady and Mark (Horace) played a pest control operative named Exterminator Jeff.
- The way Horace accidentally bumped his club into Jasper's head when trying to attack Pongo and Perdita was repeated again in The Sword in the Stone by Sir Ector, only he had a sword and didn't get kicked back by his son, Sir Kay, as Jasper did to Horace in return.
- The Milkman's truck from The Aristocats resembles that of Jasper and Horace.
- In the 1996 live-action remake, Jasper and Horace are similar to the Wet Bandits, Harry and Marv, in the popular film Home Alone and its sequel, as they too are robbers, suffer several accidents, get outwitted by the protagonists, and get arrested afterward. The notable difference is the tall one (Jasper) is the dominant one of the duo. Coincidentally, both films were written and produced by the late John Hughes.