- "He gave me this horn. I don't know if it's supposed to mean something, but when I look at it, I think of him. I just wish I knew who he was."
- ―Heather talking about her father.[src]
Heather's horn is one of her main accessories. It was given to her by the Chief of the Hairy Hooligans, Stoick the Vast, to celebrate her birth, as she was the daughter of the Berserker Chief, Oswald the Agreeable.
During the events of "Have Dragon Will Travel, Parts 1 and 2", it was revealed that the horn belonged to Stoick the Vast, who gave it to Oswald the Agreeable of the Berserker Tribe as a gift for his newborn daughter, Heather.
Also revealed in "Have Dragon Will Travel, Parts 1 and 2", for unknown reasons, Heather was separated from her father and insane brother and was taken in by a couple who raised her as their own. Heather always kept this horn with her as a reminder of her birth family, as shown in "Heather Report, Parts 1 and 2".
Also in, "Have Dragon Will Travel, Part 2", Heather tells Hiccup about her past and about how the horn was from her father. While she and Astrid are out having some girl time, Toothless begins to snoop through Heather's bag, finding her horn. Hiccup recognizes the seal on it as his father's. He then travels to Berk to get information from Stoick, even questioning if Heather was his own sister. After learning the truth, Hiccup races to tell Heather that Stoick gave the horn to Oswald for his daughter. This means Oswald was Heather's father, making Dagur, the maniac who wiped out her village and foster family, her brother. In spite of all this, Heather still kept the horn.
The horn looks similar to that of a yak, grey, sharp and long. The horn is a little worn out and filthy, possibly because of wear and tear faced over time.There are ropes twined neatly around it and the Hooligan's Chief seal carved onto it.
In Race to the Edge, she wears it on a leather belt.
- Astrid wore one like it when she disguised herself as Heather.
- The horn is similar to Fishlegs' lobster claw necklace in the books.
- In concept art, the horn has writing on it instead of Stoick's seal.
- The seal on the horn is nearly identical to Stoick's ceremonial belt buckle in "Twinsanity", which was the first episode Dagur appeared in.
- Throughout Race to the Edge, Heather's horn is occasionally out of place.