The Wall could be… full of dragons?
The ice pressed close around them, and he could feel the cold seeping into his bones, the weight of the Wall above his head. It felt like walking down the gullet of an ice dragon. - A Storm of Swords
After the first theorized mention of an Ice Dragon in relation to The Wall, the wacky world of A Song of Ice and Fire constructed a bizarre argument: what if there was an Ice Dragon asleep in The Wall? Or even more daring: what if The Wall was just made out of a massive buried Ice Dragon with a thin coat of ice on top of the hulking, slumbering mass? Taking down The Wall would just be a matter of waking the dragon (which could be done with "Dragonbinder," another magic horn, of course).
While Maester Aemon Targareyn is dying on a boat in A Feast For Crows he utters a lot of things to Sam, but one line sticks out: "I should not have left the Wall. Lord Snow could not have known, but I should have seen it. Fire consumes, but cold preserves. The Wall..." Boop. Most take this to mean Aemon thinks the cold preserved him, but the others think it means the cold is preserving something else.