Lock, Shock, and Barrel are a trio of trick-or-treaters from Halloween Town whom are very mischievous and easily influenced to aid Mr. oogie Boogie and the Villain league in a scheme of theirs.
Lock is six years old and supposedly the leader of Oogie's Boys, but does not think thoroughly and actually appears to be the least intelligent of the three. Lock wears a devil costume; his barbed tail moves as though alive, 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. 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. Without his mask he might not have horns but his handle bar style hair makes it look really close.
Shock is seven years old and the most cunning and dangerous, and the only female of Oogie's minions. She has some contempt for the other two for their supposed stupidity. 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 colour and lack of any features (except eye-holes and a nose). She is usually quick to patch up any arguments between her and her brothers, if not with the nicest methods. She knows how to bake.
Barrel is five years old, Oogie's "star pupil," and mistakenly considered the most stupid of the three troublemakers, despite his protests to the contrary. He is the butt of many jokes made by his siblings 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 back 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 pumpkins. Barrel is quick to stand up for either of his siblings and appears in fact to be the most intelligent of the three. He also unintentionally bothers Jack when asking him a number of annoying (and somewhat embarrassing) questions.
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, and he seems to wear pale orange gloves. His skin is an unhealthy grey 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, showng sharp teeth. Lock's outfit is completed by a red, pointed tail, though it is unclear wether or not this is an accessory.
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 wear sky blue lipstick (though both Barrel and Lock have lips of the same color, so this may be her normal lip color) and has deathly grey skin, the latter being a trait 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 grey-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 and dark purple gloves.
Barrel is the shortest and most rotund of the trio, sporting the same pale grey 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 arund 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. Unlike his friends, Barrel doesn't seem to wear gloves, but 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 very loyal to Oogie as they are simply making mischief to stay on his good side (in other words: they serve him 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 and sends them back. They then capture their true quarry. 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.
Role in the series
Like their boss, the trio don't prefer to show up to Villain League meetings for their own purposes. As of a result, Mirage doesn't seem to prefer hiring the three for henchmen duties only when it's necessary. Dracula and his goons, however, think they're a riot to have, and lets them in THEIR team quite often.