With Jack being the only other male in the crossover besides Hiccup, the two are usually portrayed to be good friends, though it can sometimes go beyond a platonic relationship. "Hijack" or "Frostcup", as most fans call it, originates to a time before RotBTD when Rise of the Guardians and How to Train Your Dragon ("How to Train Your Guardian") was a crossover on its own.
Since Jack Frost (Jokul Frosti) comes from Nordic myths and Hiccup is a Viking, fans believe it could have been possible that Hiccup believed in Jack, and therefore been able to see him. Also, it is said that on Hiccup's native island of Berk it "snows nine months of the year and hails the other three". Though this could be a bit of an exaggeration, it is a fact that the island has some cold weather patterns, which could be a result of frequent visits from Jack.
- I'll See It When I Believe It by Old Beginning New Ending
- Double Trouble by geminisonic
- Come What May by geminisonic
- Jack Frost's Dating Advice by Winder
- Tangled Up In Brave Lies by Thefangirlthatdiedfirst
- Just Two Strangers In A Crowd by Alome Fenwinkle
- Seasons of the Heart by Purplerose128
- Chronicles of a Meadow by Purplerose128
- A touch of Frost by Eliza-Lou-Riley