For the entire campaign Grog should be followed by some snot nose kid and a wizard who keep trying to steal the stone.
Grog wakes up one night to find them trying to steal his weapon, and the twerp can’t even lift the handle off the ground. He picks up the hammer by the head and spins around to dislodge the kid - which works, insofar as the child flies off toward the mountains, holding some kind of sword. Grog wonders where he got that, and goes back to bed.
And if INT 10+ maybe grog can figure out one day it just tilts out the side to release.
That’s it, I’m gettin’ me mallet.
This reminds me of a comic I saw a while ago where the BBEG was gloating that he could only be killed by the sword next to him that couldn’t be pulled from the stone. The barbarian picks up the BBEG and swings him at the sword.
At the end it is revealed that only the chosen could wield the sword. No one ever mentions that the sword had to be released from the stone and Grog was the hero all along. Because to be a hero you have to be strong. Foolproof selection method.