Author: Dean Koontz
I suppose that what Dean is trying to say is that life isn't meant to be competitive like who's the smartest, strongest, or the best at everything overall and to just enjoy life as it is.
I think that the significance of this quote is that when two people meet, if some sort of connection is formed, the two people will never be the same again - similar to when two elements meet in chemistry; they won't ever be the same again.
This monster symbolizes the fear inside that everyone feels just like Travis did when he was in the woods escaping some sort of creature with Einstein.
Death symbolizes what a part of this book is about like how Travis loses all of his loved ones, Nora lives alone after her aunt died, and how Vince is a hitman killing people everyday.