I am in great need of a bagging system so I asked openai its opinion re Thor vs Fenrir. This is what it said. 

Thor vs. Fenrir – A Myth Retold

As the sky cracks and fire rains down, the great wolf Fenrir bursts free of his chains. His jaws stretch wide—upper jaw scraping the sky, lower jaw dragging the earth—devouring everything in his path. In the original prophecy, it is Odin who stands before him. But this time, Thor, the thunderer, steps forward.

Mjölnir crackles in his hand, lightning arching along the haft. The ground trembles beneath Fenrir’s steps.

• The first clash: Thor hurls his hammer into the wolf’s chest. The blow knocks Fenrir back, bones shattering, but the beast’s rage only grows. He lunges, teeth snapping at Thor’s shield arm, ripping the metal to tatters.

• The struggle of strength: Thor grabs Fenrir’s upper jaw with one hand, his lower jaw with the other, straining to hold the monster apart. The wolf thrashes, each movement quaking the Nine Worlds.

• The storm unleashed: With a roar, Thor summons thunder and lightning into his body, channeling it through Mjölnir. He drives the hammer down into Fenrir’s skull. The blast blinds all who see it.

• The price: Though the wolf collapses, its venomous blood splashes onto Thor, burning through flesh and bone, just as Jörmungandr’s poison would have. Thor staggers, victorious—but doomed. He walks nine steps before falling, his body smoking, his spirit bound for Valhalla.

I planning my escape from 10x10 Tentville and want to build a freestanding, insulated fruiting room. Thinking roughly 12x24 on a concrete slab with a couple of trench drains but I don't know what material I should use to construct the walls and roof. Wood frame?