Shamash bampfs back, cliffside.
The dragon is all full of piss and searing acid about the noise(s) made by the whirligig(s). After some cursory attempts to get him to just leave, the party fights him, employing the same pushing-off-ledge strategy that worked with the pathetic gnolls. Surprisingly, it works for the dragon also, despite his wings, though it does take two 100+ foot drops to knock him out, and an execution-style brain-splattering magic missile to finish the deed.
Said killing blow was delivered by Marvin after leaping deftly off the cliff and feather-falling 1000 feet down to the floor of the canyon, all in search of the coveted dragon’s hoard. After some travails, Marvin locates the hoard in an underground burrow, discovering a dragon twice the size of the other sleeping atop it. He flees, narrowly avoiding certain death after waking the dragon by hiding as hard as he can until it goes back to sleep.
There is much arguing over how (and even whether) to get Marvin back up the cliff. All anyone can agree on is that someone has to go down there, and rope is involved somehow. Marvin insists fey stepping, not climbing, is the strategy. After many high jinks, the end result is Marvin and Shamash trading places, as Shamash just can’t summon the stamina to drag his giant dragon frame back up. Lying at the bottom of the cliff, peacefully watching the stars come out, he checks on the sending stone to see that everyone made it up safely, and bampfs, putting himself once more in the hands of the bampf god, who always seems to return him to his party eventually.