Morose Marvin
One day he took a break from his work and realized he had never explored any of the other tunnels in the complex. He peered into the darkness of one of the tunnels, listening intently.
Nothing.
Marvin grabbed a flashlight from the storeroom and entered the tunnel. He followed it a long way as it went uphill, zigging and zagging on the way. He breathed hard with the effort of the climb.
Eventually the tunnel leveled off and branched out into a network of passages. At regular intervals the ceiling changed; in some places it extended up for an extra few feet, and in other places it was marked with a large "X" painted on the ceiling.
Sometimes the ceiling was low enough to actually touch with the flashlight when he stood on his tip-toes. He picked curiously at one of the X's.
Bits of dirt and rock started to crumble from the ceiling. It began raining down faster and faster. Marvin jumped back just in time for the ceiling to completely give way, dropping rocks and filling the passage with choking dust.

Written, illustrated and Copyright © 2001 by Kevin Kelm