'The Subway Piranhas'

Did anyone tell you
that in each subway train
there is one special seat
with a small hole in it
and underneath the seat
is a tank of piranha-fish
which have not been fed
for quite some time.
The fish become quite agitated
by the shoogling of the train
and jump up through the seat.
The resulting skeletons
of unlucky passengers
turn an honest penny
for the transport executive,
hanging far and wide
in medical schools.

      -- Edwin Morgan