I killed an insect once,
Crushed it with a rock.

I had to; its fate was already decided:

This insect had too few legs; they bent away
From its body as it struggled proudly towards
Nothing and indeed found nothing.

Pity took shape and brought an end to its odyssey:
Yielding to the rock, it accepted that it had just come across its noblest hope for a way out.

Fear took hold of me;  my own rock was sure to come
Soon enough.