Trantor is the main antagonist of Ernest Scared Stupid. He was an ancient evil troll who desperately wanted to kill Ernest P. Worrell who is the descendant of the known "troll fighter", Reverend Phineas Worrell, who stopped his plans of resurrecting the evil troll race and overthrow humanity.
Trantor among his treacherous kind followed a group of settlers from England to Briarville, Missouri in America and has been plaguing them for many years. In 1891, Trantor almost captured all of five human children in his effort to use their life force to resurrect his people. Fornately he failed when he tried to take away a young girl who was used a bait for the men of Briarville to trapped the troll. The village elder, Rev. Phineas Worrell who lead the men to trap Trantor, put away the accursed troll by sealing him in the earthen soil under an oak tree in the woods. But Trantor was not finished: he made a prophecy that a direct descendant of Phineas's family would one day, release him from his earthly prison on the full moon night before All Hallows Eve (Halloween), so that Trantor would be free to complete his mission of bringing forth his offspring of trolls, thus unleashing a deadly army of trolls upon the world. In addition, Trantor placed a curse on Phineas that his descendants would become dumber with each generation which would be proven useful to the sinister troll's advantage.
Fast-forwarding to the present day, Ernest is a sanitation engineer and he is ordered to clean up the land of the superstitious Francis "Old Lady" Hackmore, who is actually the sister of one of Trantor's original four victims. However, when she learns that Ernest is a descendant of Phineas, she drives him away. Meanwhile, Ernest's middle school friends, Kenny, Elizabeth, and Joey, are working on a haunted house, only to have it destroyed by the neighborhood bullies. Ernest suggests that they build a treehouse so they have the high ground. After much searching, they discover a tree which Ernest deems perfect, unaware that it is the same tree that feeds on the energy of Trantor's victims to grow pods which hatch into trolls upon touching the ground. After building the treehouse, Lady Hackmore sees what Ernest has done and goes into a frenzy. It is then that Ernest learns of the legend of Trantor and that 'he' can release it. Skeptical, Ernest performs the ritual for the kids (by touching the tree and saying "Yeah I call thee forth, Trantor!"), and inadvertently releases the troll. Scared stiff, the kids run off, leaving Ernest alone in the tree, where Trantor attacks him. At that moment, Ernest kicks over a cooler and milk spills out, causing Trantor to run off.
After running a distance, Kenny, Elizabeth, and Joey go off to their respective homes. On his way, Joey falls into a muddy hole. Screaming for help, Joey feels his hand being grabbed. Hearing Ernest's voice, Joey thinks that it's him, only to look up and see Trantor, who transforms him into his first wooden doll (as punishment for bad acting) and places him in the tree, causing the pods to start sprouting. Ernest attempts to tell about his encounter to Kenny's father, the sheriff, but he doesn't believe him, so he goes to Ms. Hackmore. After consulting the legend of Trantor from the book "Trolls and Tree Devils", it is learned that the only thing that can stop Trantor for good is "the heart of a child and a mother's care". Being the descendant of Phineas, it's up to Ernest to save the town. He attempts to mount a defense against Trantor, but the townspeople do not believe his story and refuse to provide assistance (except for Chuck and Bobby Tulip, who take advantage of Ernest by selling him phony troll weapons). Meanwhile, Kenny and Elizabeth return to the treehouse, looking for Joey. There, they discover Joey as a wooden doll and see the pods. At that same moment, Trantor returns and see the two children. Hearing the troll coming, Kenny and Elizabeth run to Ms. Hackmore's, with Trantor following. Just as he's about to get them, the troll sees a boy on a skateboard.
Deciding to get Kenny and Elizabeth later, Trantor abducts the boy and carries him to the treehouse, turning him into his second wooden doll(as punishment for bad acted). He is one step closer to releasing his army. The town doesnt believe Ernest and they care more about the Halloween dance more than the children. Ernest and Kenny form a troll-fighting squad and set up traps around the neighborhood. While at home, Elizabeth tries to make her mom believe what Ernest is saying is true, but she doesn't believe it. Hearing something under her bed, Elizabeth looks and only finds her stuffed bear. However, when she turns around, she sees Trantor sitting by her. The troll has claimed his third victim (as punishment for bad acting). Spotting Ernest at a store, Trantor decides to take a second chance at killing him. The cashier Jimmy sees the troll and tries to alert Ernest, but he speaks in gibberish. When the cashier Jimmy pulls out a gun, Ernest throws the milk he was holding in Trantor's direction, causing the troll to once again flee. Kenny soon meets up with one of his friends when he hears Elizabeth voice coming from a pipe. Investigating it, Kenny doesn't see anything, but when he turns around, he sees Trantor turn his friend, Gregg (who is dressed as a Native American) into his fourth wooden doll, (as punishment for bad acting) with plans to make Kenny #5.
The troll chases Kenny but vanishes when the milkman's truck drives between him and Kenny. Meanwhile, the parents go to the sheriff, but the sheriff thinks the children are at the school. Kenny then tries to tell his father what he saw, but he won't listen. Ernest then shows up saying he caught the troll, only when he opens the truck, it is revealed he caught the neighborhood bullies, who are also the mayor's sons. Enraged, the mayor fires him. Kenny tries to back up his story, but his father takes him away to the school Halloween dance. Ernest is about to throw in the towel but is re-inspired by Rimshot, Ernest's Jack Russell Terrier, to keep up the fight. Trantor takes his latest two victims to the tree so their souls can feed his pods. He only needs one more child to unleash his army. Ernest and Rimshot come to the tree and see the pods, deciding to tell Ms. Hackmore, only to have Trantor attack them on Ernest's pickup truck. After escaping the troll, Ernest looks over the legend of the troll and sees that trolls can be destroyed with something called M-I- -K. The audience knows that it means milk ("a mother's care"), but Ernest thinks that the answer is Bulgarian miak.
Knowing that Trantor needs one more child, Ms. Hackmore deduces that Trantor will head to where the children are: the Halloween dance at school, which he does. Upon arriving at the school, Ernest rushes in to warn everyone about Trantor. Ms. Hackmore is about to follow him when shes sees a little girl fighting with her mother then make up, making her realize that unconditional love ("the heart of a child") is the key to defeating Trantor. During the costume contest, one of the mayor's sons picks a fight with Trantor, resulting in him turning the boy into his fifth and final wooden doll (as punishment for bad acting). Ernest attempts to destroy the troll with miak, but it doesn't work and he ends up getting thrown into the ice cream machine. Rimshot tries to help, but Trantor transforms him into a wooden dog. Trantor is about to destroy Ernest when he sees him covered in ice cream and flees.
Seeing what the troll had done to his dog, Ernest is then determined to take him down. The townspeople, led by the mayor, decide to go to the treehouse and stop the troll. At the same time, Kenny realizes that the troll can be destroyed by being exposed to milk, and rallies together a group of the local children, including the mayor's other son. Trantor reaches the tree first and places his final wooden doll into it, allowing him to free his army. As Trantor laughs madly over his success at last, an enraged Ernest arrives and rams Trantor with his pickup, only for Trantor to manage to escape. Ernest then sees that the pods are larger than before. The pods begin falling off the tree. Ernest attempts to keep them from hitting the ground, but fails and Trantor's army literally rises. Meanwhile, Kenny and his troop obtain milk products and water pistols from a convenience store (Same one where Trantor tried to get Ernest, and much to Jimmy's anger due to them riding their bicycles in the store) and head to the treehouse on their bicycles.
The townspeople arrive and are instantly overtaken by numerous trolls. Trantor orders his army to bring him Ernest's head. At that moment, Kenny arrives and spritzes the trolls attacking his father with milk, vaporizing them. Following his lead, the rest of the children begin attacking the trolls with milk. Just as Ernest is about to be decapitated, Kenny sprays his executioners. Mounting their attack from the treehouse, Ernest and Kenny soon take down the entire troll army. Everyone thinks that they have won, but Ms. Hackmore appears during the cheering saying that it's not over yet. At that moment, Trantor appears. During the battle, he had called upon dark spirits to strengthen him, making him more repulsive than ever. Knocking Ernest out of the tree, Trantor corners Kenny, who immediately sprays him, but he has grown so strong that he is immune to milk, and transforms Kenny into a wooden doll (as punishment for bad acted), making him even stronger. Jumping out of the tree, Trantor faces off Ernest in their final battle, trapping everyone else behind a wall of fire.
Ernest initially attempts to fight Trantor with milk, but he hears Hackmore say that only unconditional love can stop him. Ernest embraces Trantor and begins dancing, overwhelming the troll with love and affection, finishing with a kiss (him and everybody were disgusted) causing him to explode. With Trantor destroyed, his spell is broken and all the wooden figurines revert to normal since their punishment is over, including his original four victims from the 19th century which Ms. Hackmore had watched over since Trantor's imprisonment. As Ernest watches everyone being reunited with the loved ones, he feels that there is nothing for him, until he sees that Rimshot has also returned to normal.