When Gobber sarcastically suggests making a pair of earrings out of the last bit of Gronckle Iron in The Iron Gronckle, Gunnar raises his hand, wanting them, but Gobber tells him, "Not gonna happen, Gunnar."
One spring, Barf and Belch started collecting eggs around Berk, and the Hairy Hooligans wanted some for themselves. They discovered that by poking the eggshells in one spot, they could extract the inside without damaging the rest of the egg. Gunnar then came up with the idea of painting the eggs that have already been hollowed so that they don't poke them again.
Gunnar has the same appearance and character design as Sven, down to the braided brunette beard.