Jack Zweiblumen
Twoflower's alternative identity, when temporarily translated to an airliner flying above Roundworld in order to escape plummeting to his doom from a suddenly non-existent noble dragon.
For further information as to how he and Rincewind ended up crossing the vast gulfs of interdimensional space - only to be snapped back to the Discworld reality again by the arrival of the Luggage - go to Dr Rjinswand.