Long ago, when Jellybean was just a puppy, he was found by Tontu. Tontu decided to adopt him, as they did what Nisses do with lost things: take them home with them. Jellybean was looked after in secret for a while, but one day, Tontu's parents found Jellybean and they took him away, despite Tontu's pleas. Most likely, this was done because Tontu's father knew how big Jellybean would eventually become.
As time passed, Jellybean grew bigger, and became a threat to the Trolberg citizens. Still loyal to Tontu, he tried to find his former owner. Due to being raised by a nisse, he had learned to enter and leave Nowhere Space on his own, and used this to stalk the city without anyone being able to find him. Since as early as "Chapter 6", sightings of him were reported around Trolberg, with people addressing him by names as "The beast of Trolberg" and "The Black Hound". As he navigated the nowhere spaces, he accidentally trashed several homes, leading to the nisse living there being blamed and getting banished by the home owners.
In "Chapter 10: The Storm", a news report about him was shown when Hilda turned on the television during the storm, but due to the weather outside, the channel was messed up, and Hilda turned off the television.
In "Chapter 12: The Nisse", news and rumors about sightings began to spread around the city. The news channel Johanna turned on later also reported about how the number of sightings was increasing and it was the main talk of the town. After learning more about it, Johanna had doubts about Hilda going on her Sparrow Scout Camping Trip because of the creature out there, but some sightings were considered fake ones or other things besides The Black Hound, which relieved Johanna.
While driving to the camping grounds for Hilda's overnight camping trip, Johanna caught a glimpse of Jellybean between two houses, but when she turned to look back, he was gone. Later, during the trip, when Hilda and David found out that Frida was actually hanging out with some Marra, David heard a rustling in the bushes and assumed it was the Black Hound. Panicking, he fleed, and tripped, where he grew even more frightened, ran into Hilda, and intercepted into the Marra's gathering. Jellybean's final appearance in this episode was when, while David was standing up to the Marra himself, Jellybean suddenly appeared right behind him, causing everyone to back away in terror.
In "Chapter 13: The Black Hound", Kelly tried to feed Frida to the hound while the Marra fled, but Hilda managed to distract Jellybean with a bag of chips. When Raven Leader heard about Jellybean being sighted near the camp, she had the camp called off early and send everybody home. A day after the camping trip, after Hilda tried to get a Sparrow Scout Badge and find Tontu and was unsuccessful with both. Meanwhile, Jellybean consumed three humans, and the Trolberg Safety Patrol was tasked with hunting the beast down.
Then, during the badge ceremony at the Scout Hall, Tontu (alpha) found Jellybean hiding in the Nowhere Space of the building. He quickly warned Hilda, and dragged her along into Nowhere Space. There, they traveled from building to building, stalked by the hound. Eventually, they ended up in Hilda's house, where Jellybean was finally reunited with his Tontu. This calmed him down, and Tontu even made him hurl out the three humans he ate earlier.
The danger was not over yet, since the safety patrol was still hunting Jellybean. Their sirens made Jellybean panic, and he ran outside, where the safety patrol tried to capture him with nets, with no success however. Hilda, Johanna, and the two Tontus came to his rescue and tried to lure him out of the city walls with Johanna's car. Jellybean caught up with the car, jumped on the roof, and blocked Johanna's view, causing the car to go out of control. To get rid of the safety patrol following them, and prevent the car from crashing into the city wall, the two Tontu's did the one thing no nisse would usually ever dare; enter the Nowhere Space of the outside world.
The gamble payed off for Johanna, Hilda, and Tontu (alpha), who ended up outside the city walls. Jellybean and his owner, however, vanished into the Nowhere Space. At the end of the episode, it was revealed they eventually got out as well, and had ended up in the wilderness near the remains of Hilda's old home. There, they encountered some Elves and the Wood Man, who told them a bit more about Hilda and her history with the giant Jorgen.
Jellybean does not appear in Season 2, leaving it unknown what became of him.
In the Graphic Novels, Jellybean only appears in "Hilda and the Black Hound". Unlike the animated series, there is nothing foreshadowing him in the earlier stories.
His role in the graphic novel is largely identical to the animated adaptation, with a few changes: he is first seen by Hilda and Johanna the same night Hilda joins the Sparrow Scouts (in the animated series, these events are spread over separate episodes). The scene with the Marra never happens since the Marra are exclusive to the animated series. There are two additional scenes where Hilda sees Jellybean (once near the camp site, and once in Trolberg), but the beast doesn't harm her. And at the end of the story, instead of getting out of Nowhere Space near Hilda's old house and meeting the Wood Man there, Jellybean and Tontu are shown to have emerged in an undisclosed location that strongly resembles one of the outer islands of Fairy Country but is not identified as such.
The events from chapters 12 and 13 are adapted into the book "Hilda and the Nowhere Space". Unlike the animated series, Jellybean is not hinted at or foreshadowed in the previous two books.
Jellybean's role in the book is mostly identical to the animated series. The book does however add an additional scene in which Hilda follows Jellybean out of the city and into The Great Forest, and thus discovers Jellybean has made a nest for himself there, in a hole under the roots of a bristle cone. She tries to tell this to the authorities, but the Trolberg police has already handed the Black Hound case over to the Safety Patrol, and they have no authority outside Trolberg so they can't investigate the nest. The book does not reveal what became of Jellybean and Tontu after they entered the Nowhere Space of the outside world.
