What Lurks Below? [Lyric Poem]

I'm swimming in the lake -
miles from one and all,
feeling peace and calm - when
the monster comes to call.

What could drag me under?
I'll never, ever know.
Some will always wonder
what caused the undertow.

The lake is surface calm,
and should be at its depths,
but in its muck lie bones
of those pulled under breath.

Some will swim tomorrow,
and in the days to come.
Most will come and go,
and just feel blissful numb.