Mervyn apparently drove a bus in dreams for a time during Dream's extended absence, and is first seen briefly in the Preludes and Nocturnes Passengers issue, when Morpheus travels through the dreams of others, "I travel briefly by bus...I sit at the front and talk to the driver." The driver of the bus was a pumpkin headed, cigar smoking figure.
Merv is in charge of the construction, maintenance, and demolition work in the Dreaming, though he sometimes complains that his job is superfluous since Dream can change any of it at will.
In a past incarnation, shown in The Wake, Mervyn was seen to have had a turnip for a head instead of a pumpkin, as pumpkins were not then known in Europe.
One issue of the "Dreaming" spin-off comic focuses on a dreamer who enjoys working under Merv's supervision.