Doppler Geoff

From Frikipedia

A Geoff that moves past you at high speed, perhaps because she is travelling on the tube or a bus. On second thoughts, probably not on a bus.

The Doppler Geoff is an elusive breed, passing tantalisingly briefly through one's life before disappearing, never to be seen again. But Frikipedia is grateful to her for the many tedious journeys on London public transport that she has made that little bit more bearable.