A flying birthday cake?

Marvin cannot get to sleep. It's late, the ground is hard in Nick Tuffle's garden, he is far too full on cake and he has drunk too much punch. Then he hears a low humming noise. He feels the earth shudder beneath him and there is a bright flash - sort of the same colour as the green icing on Nick's birthday cake. Is he dreaming or was that a flying birthday cake, candles aglow? Perhaps something much stranger is on the horizon . . .