Lock is six years old and the leader of Oogie's Boys, but does not always think thoroughly and actually appears to be just the second most intelligent, if not Shock's intellectual equal. Lock wears a devil costume; his teeth are pointed sharply, his face is narrow and long-jawed, and his hair is waxed into two horns making him, literally, a handsome devil. His barbed tail is actually real and connected to his body. He loves being large and in charge, and gets upset when others insult him or take the lead. However, he goes along with others' ideas if he cannot come up with anything himself. He proves himself to be right occasionally, such as when he insisted Santa Claus can fit into anything (i.e. chimneys, Oogie's sacrificial shoot). Without his mask, he might not have horns, but his handle bar style hair makes it look really close. Judging from his lines in the film, he appears to be the most violent and malicious of the group, making him the most dangerous of the three.
Shock is seven years old and the most cunning, the most intelligent, the most skeptical, and the only female of Oogie's minions. She has some contempt for the other two for their supposed stupidity, and often challenges Lock for leadership, but ends up following his orders anyway. Shock wears a purple witch costume with an elongated hat. There is no difference between her mask and her face, other than the former's green color and lack of any features (except eye-holes and a nose). She is usually quick to patch up any arguments between her and the boys, if not with the nicest methods.
Barrel is five years old, and considered the stupidest of the three troublemakers, despite his protests to the contrary. He is the butt of many jokes made by his cohorts but usually gets even through his own tricks at which he always gets away with. Barrel wears a skeleton costume and has deformed feet, but otherwise resembles a small human boy, albeit one with white skin, sunken eyes, and perfectly combed green hair. His face is round and has a perpetual grin, except when he is angry. Barrel is usually the pilot of the walking bathtub the trio use as transport. He also likes to eat lollipops.
Lock is dressed as a devil, wearing a plain, long-sleeved, tattered red shirt, and pants of the same color. His brown shoes have pointed toes that curl upward. His skin is an unhealthy gray color, his eyes are an eerie yellow and his lips are sky blue. His upper eyelids are a pink color, while the lower one is periwinkle. His chin is rather large and the top of his head is quite flat. His ears are set rather low on his head, and his eyebrows are the same shade of red as his clothes, while the rest of his hair is a darker red-brown color. He styles his hair in such a way that he has two "horns" in the front. His nose is pointed, but not nearly as large as Shock's. His mask is a faded red devil's face with horns that curve upward much more than Lock's hair. The mask's mouth is curled into a ghastly smile, showing sharp teeth. Lock's devil-like tail is actually real and connected to his body.
Shock, the only girl of the group, is the tallest, being only slightly taller than Lock, as well as the thinnest. She is dressed as a witch, wearing a purple witch's hat that is about the same height (perhaps even taller) than her. Her hair is wiry and blue, the same color as the makeup she wears around her eyes. She also seems have blue lips and has deathly gray skin, both being traits all three children share. Her face and neck are quite long and her nose is enormous and pointed, taking up most of her face. Shock's mask is a plain green one that sports the same large nose as her own face, and its mouth is set in a deep frown. She wears a pink dress with a dark purple hem, as well as black boots. Aside from her face, her skin appears to be a dark, almost black, purple.
Barrel is the shortest and most rotund of the trio, sporting the same pale gray skin and blue lips as his friends. His head is spherical and he has short, pale green hair. His nose is very small when compared to Lock and Shock's, and it is upturned. His eyes are quite close together and appear to be sunken in, though this could just be an illusion created by the dark makeup around them. Barrel dresses up like a skeleton, wearing tattered purple pants and a like-colored shirt. Both of these pieces of clothing are decorated with bones roughly corresponding to their locations in the human body. His feet are oddly shaped, with three toes of the same length. It isn't clear if they are part of his costume or his real feet. His mask is that of a skull; a simple, round, white mask with the mouth being bare teeth set in a wide grin, reflecting the fact that Barrel himself is usually grinning.
They are also not completely loyal to Oogie as they are simply making mischief to stay on his good side (in other words they serve him at least partly out of fear) and would prefer to do harmless fun which they seem to enjoy more. Instructing them to "leave that no-account Oogie Boogie out of this!", Jack sends Lock, Shock, and Barrel to "Kidnap the Sandy Claws" (the Halloween Town residents' mistaken name for Santa Claus). At first, they accidentally capture the Easter Bunny, whereupon Jack apologizes to it and orders the trio to take the bunny home. They then capture their true quarry after a good many days. The trio take Santa Claus to Oogie's lair, where Oogie taunts and threatens Santa. Shortly after Jack defeats Oogie and rescues Santa Claus, a hatch above opens and Lock, Shock, and Barrel appear, having led the Mayor to Oogie's lair. In the deleted scenes, a sequence shows Lock, Shock, and Barrel spectating as Oogie tortures and teases Santa Claus and Sally the rag doll. They watch from their moving cage that hangs on a rope; Jack slips down and scares them away before entering Oogie's lair. The only time their names are mentioned in the movie is the scene they say them to the mayor, arguing that Jack had sent for them by name.
Jack, once again tired of the same old tricks for Halloween, leaves town in search of new ideas. In his absence, Lock, Shock, and Barrel resurrect their master Oogie Boogie, allowing him to inflict terror over Halloween Town once again. Oogie kidnaps the Holiday Leaders for Valentine's Day, St. Patrick's Day, Thanksgiving, Independence Day, and Easter, and imprisons them in his underground lair. Lock, Shock, and Barrel are entrusted with hiding each of the seven Holiday Doors in each area of the town where they wouldn't be discovered. They also raise armies of ghosts and skeletons to counteract Jack's inevitable attempt to fight upon his return. Shortly after Jack comes back, he encounters the trio in the Graveyard, and they refuse to reverse the damage.
Lock engages him in battle, and retreats after his skeletons are defeated. When Jack goes to free Sally, Lock fights him once more, this time entering the fray himself, but loses again. Soon after, when Jack attempts to free Dr. Finkelstein, Shock confronts him with an army of ghosts, but retreats upon losing. She confronts him again at the Doctor's Lab, using giant metal balls to deter Jack from climbing the spiral ramp to the lab. Like Lock, Jack warns her to stop helping Oogie, and like Lock, she agrees, but crosses her fingers behind her back. They're next seen at the Pumpkin Patch, where Barrel forces Jack to navigate a maze he's created to reach him in the Big Pumpkin Head. Upon succeeding, Jack fights Barrel and the skeletons under his control, taking from him the Thanksgiving Door and the key to the Residential Area. When Jack reaches the Mayor's house, he finds Lock, Shock, and Barrel on the roof, where they face off one last time.
Upon their defeat, Jack claims the Independence Day door, but the trio use a trick switch to open a void beneath him, dropping him into Oogie's underground lair and remarking, "Looks like he really fell for that one." They are not seen or mentioned for the remainder of the game after this.
Lock, Shock and Barrel appear as antagonists in the world of Halloween Town in several installments in the series, regularly serving as morally ambiguous goons of Oogie Boogie.
In the original Kingdom Hearts, Lock, Shock and Barrel learn that Jack and Dr. Finklestein were working together to create a heart. Knowing Oogie has a goal to control a hoard of creatures known as the Heartless, the trio inform Oogie of Jack's latest endeavor, and are immediately sent to steal it. After doing so, Jack, Sora, Donald, and Goofy, follow them to Oogie's lair where they're defeated and forced to surrender.
In Kingdom Hearts II, Lock, Shock and Barrel are seen serving as Dr. Finkelstein's assistants. After intentionally causing mayhem during the doctor's latest experiment, the trio run off into town, eventually bumping into Maleficent, who recruits the trio in her plot to turn Santa Claus into a Heartless. After a while, Lock, Shock and Barrel mention Oogie, who was killed in the original game by Jack and Sora. His mention promote Maleficent to revive the boogy man, enlisting him in assisting her, as well, while Lock, Shock and Barrel are left to battle Sora and Jack with the aid of a giant Heartless, though they soon meet defeat.
In the second visit, they are blamed for stealing Christmas presents from Santa. In the inevitable chase afterwards, Jack and Sora learn the trio were only looking for parts for the doctor's experiment, proving themselves to be innocent.
Lock, Shock, and Barrel make an appearance in Bleedman's popular webcomic: Grim Tales Down Below. They've kidnapped Grim Jr. and taken him to their treehouse.
Though Lock is the leader of the trio, it was not until Kingdom Hearts his leadership was confirmed.
Though they appear to have reformed at the end of the movie, all appearances after the movie have Lock, Shock and Barrel reverting back to being antagonists.
Though it seems they are not completely loyal to Oogie, seeing their supposed reformation, they went as far as to bring him back to life, suggesting they enjoy working for him more than being good.
Their names as a whole is derived from wordplay of the phrase "Lock, stock, and barrel," a phrase meaning 'everything', which in turn was derived from the components of a musket.
Despite generally being considered antagonists, the trio is meant to emulate how real children their age act (although, obviously, with an increased fascination for the morbid and the macabre, being citizens of Halloweentown).
In German, the trio is voiced by an all-male rock band; because of this, Shock (who is female) is voiced by a man.