This is when Taking a Level in Kindness is plot-required. Sometimes, an otherwise mean person becomes a Nice Guy unexpectedly, most likely to advance the plot or sometimes simply for humor value, or for a positive moment.
In-story, the sudden change in behavior can have a variety of reasons. Sometimes they're mundane everyday reasons such as merely being in love with someone. It can also often happen in Christmas specials. Others could because of certain scenarios; maybe that one character comforts the other character in distress. Sometimes the Kindness Ball is a more literal thing, such as cake. Of course, supernatural, paranormal or abnormal items being the literal Kindness Ball is common too.
Opposite of Jerkass Ball.
May overlap with Not Himself, Nice Job Fixing It, Villain!, and Depending on the Writer. If done in a particularly exaggerated manner that in no way befits their normal characterization it is likely an Out-of-Character Moment.
Despite being a temporary change of personality plot wise, characters can eventually snap themselves out of it, leading to a We Want Our Jerk Back! scenario.
- Harry Potter and the Deathly Hallows finally has Percy Weasley removing the giant pole up his rear end and showing affection towards his family. This coming from the guy who pretty much disowned them after joining the Ministry of Magic, returned the sweater his mother knitted for him, didn't even visit his injured father in hospital, and had to be pressured by Scrimgeour to visit his family which was actually a ploy to for the Minister to talk to Harry.
- Blackstar from Warrior Cats, known for being a difficult cat to get along with at best and an outright villain at worst, was very nice to the cats who went to fight the beavers and return water to the lake, offering them prey when they wandered into ShadowClan territory. Lampshaded by Lionblaze, who asks, "Who are you, and what have you done with Blackstar?"
- Jessica Jones: Jessica is known to be a very rude, cynical, sardonic and pretty much pushes everyone but a select few people out of her life. However, she has a soft spot for those who are victims of the mind controlling villain known as Kilgrave. She will go out of her way to help these people and keep them from coming to harm.
- The Big Bang Theory: Sheldon, who is known for being a jerkass, shows sympathy to Howard after his mother dies, because Sheldon's father died and he understands the pain of losing a parent.
- Victor from House of Anubis has had a few of these, most of them occurring in a moment of surprising affection for the kids, saving them twice from Rufus Zeno. However, a more noticeable example happens in season two when Vera is petrified by Senkhara. With the only way to free her being to give the students all the reflectors and let them move ahead in the game, that's exactly what he does, and his out of character attitude is noted by the students.
- Fraggle Rock: In the episode "The Great Radish Caper," Junior Gorg, who is known for trying to catch and thump Fraggles, takes this after wandering about in search of a friend, dragging Mokey along so she can help him recognize a friend when he finds one. When he realizes how much Mokey misses her friends, he brings her back to the garden, despite not having found any friends of his own, and lets her go home.
- Daffy Duck takes the role of King Arthur in Bugs Bunny in King Arthur's Court. While still a rather apathetic and self-preserving figure, he is rather compliant and friendly to the requests of Bugs Bunny (who he is usually a bitter rival towards) and even willingly hands him the crown during the climax.
- Kiki the gorilla (a parody of Koko the gorilla who loved cats) from the Animaniacs Rita and Runt episode, "Kiki's Kitten" is isolated from the other gorillas because she is so aggressive toward them and she is so aggressive in general. However, cats and kittens, including Rita and the orange female cat in the episode, are her Kindness Ball, although she can be rough with them.
- Gargoyles: Xanatos is normally a morally gray business man known for his complex schemes and has fought with the protagonists a number of times. What makes him finally settle his quarrels with the protagonists is him having a baby and the protagonists helping him out when said baby is threatened.
- The Jetsons has an episode that has Cogswell Cogs build their corporate headquarters six inches over the property line. Cosmo Spacely, Cogswell's competitor, exults at this fault until it's revealed that the plans were upside-down. It's Spacely's building that's intrusive. Rather than crushing his longtime nemesis, however, Cogswell allows Spacely to buy the building and its plot from him.
- The 1957 Merrie Melodies cartoon Zoom And Bored sees The Determinator coyote try using a huge harpoon gun upon his prey. However, the harpoon's reel line loops around the coyote's ankle, and takes the poor critter on a wild ride across cacti, under rocks, into traffic, and into the path of a locomotive. Coming to rest atop a precipice, the coyote gasps in relief and amazement that he survived this ordeal relatively intact. The Road Runner zips into position unnoticed behind the coyote, poised to "beep beep" his adversary over the edge with fright, as he is wont to do. Instead, the Road Runner, Breaking the Fourth Wall, addresses the audience by Talking with Signs that read "I just don't have the heart," before zipping away offscreen, iris out.
- My Little Pony: Friendship Is Magic: In "Magic Duel", Trixie seizes control of Ponyville and goes on a power trip, sealing the whole town under a glass dome and preventing any pony from entering or leaving. She makes one exception in her reign of jerkassery: briefly lifting the seal so a group of beavers can carry a log out of the town. And that proves to be Trixie's undoing—Fluttershy is hiding in that log, and she carries a crucial message out to Twilight Sparkle, who saves Ponyville from Trixie shortly after.
- Mr.Burns from The Simpsons can hold this ball in some episodes. The best example of this was in the episode "King-Sized Homer", where he did everything from leading a calisthenics session, to politely pushing Homer back when Homer slides into his office on an oil slick, to honoring Homer's gambit to be considered disabled, to agreeing to do whatever Homer wants in exchange for saving the plant. (which ended with him paying for Homers liposuction.)
- In The Amazing World of Gumball, Mr. Robinson, Miss Simian, and several other "mean" characters have a lot of these.
- Bender in Futurama is normally a classic Jerkass, but in episodes focusing on him, he tends to develop a noticeably more empathetic and kind side (which is strange, since one episode explicitly claims him to have a Lack of Empathy). "Godfellas" is probably the preeminent example, where he's shown genuinely doing his best to help the Shrimpkins (well, after the Single-Precept Religion is in place, anyway), and being downright miserable when his attempts go south.