Sassafras

Sassafras is a plant mentioned in the Dragons: Race to the Edge, Season 5 episode, "Dawn of Destruction".

Description
Sassafras, specifically White Sassafras (Sassafras albidum), is a tree native to the Eastern half of the United States. It was wide deciduous leaves that are deeply lobed. Fruits are small and blue-black in color, with a single seed inside.

In the Franchise, Sassafras is depicted as a shrub with green pointed leaves. The fruit, however, appears to be depicted correctly.

"However, I'm ecstatic to tell you that the oil you seek can be found in the rarest of Sassafras albidum plants that grow only on the Isle of Thizzian, the location of which I have included for you in its description."

- Trader Johann

Function
In the How to Train Your Dragon Franchise, Hiccup needs the oil of the sassafras plant for an undivulged reason.

In actuality, safrole oil is extracted from the sassafrass plant. It has some culinary and traditional medicinal uses. All parts of the sassafras are edible, and was historically a flavoring for root beer. Native Americans used it extensively in cooking, as a preservative, a wound treatment, and the wood was good for fires as the oils are flammable. However, research as established that sassafras may cause liver damage, mainly from the safrole content. Safrole is also used in the production of the illegal drug, MDMA (Ecstasy).

Dragons: Race to the Edge, Season 5
In the episode, "Dawn of Destruction", Hiccup needs the oil of the sassafras plant for an unknown purpose. Johann is unable to acquire it, but instead sends Hiccup to the Isle of Thizzian where he can harvest sassafras for himself. Hiccup and Astrid leave Dragon's Edge to go to the island to get the plants and spend some time together.