In the battle for survival, chemical weapons can be a huge advantage. For millions of years, animals across the globe have been locked in an evolutionary arms race of the toxic kind. As predators honed fast-acting and deadly venoms, prey fought back with potent poisons and clever delivery systems. It’s led to an array of chemical cocktails so complex and unique that science is only just beginning to unravel the mystery of how they work. They enable creatures as diverse as spiders, snakes and jellyfish to immobilise opponents many times their size in a single strike. Across two episodes, this series gets up close and personal with some of the world’s most toxic animals, to understand how they target their victim, what chemistry they use to tailor their attack and how humans can best survive it.