Runaway Co-evolution
When peacocks compete for mates, tails grow until they nearly kill the birds. When streamers compete for subscribers, spending reaches $126 billion annually - far beyond what any rational analysis would recommend.
Arms races that escalate to extremes, producing traits far beyond what's optimal in isolation. Sexual selection creates runaway dynamics: female mate preferences select for exaggerated male traits, creating positive feedback (Fisher's runaway selection, 1930). Peacock tails exemplify this - escalation continues until counterbalanced by survival costs. Tree height in forests also exemplifies runaway: competitive escalation for light drives heights far beyond optimal if trees didn't compete.
Business Application of Runaway Co-evolution
Runaway dynamics in business occur when individually rational escalation produces collectively irrational outcomes - a Prisoner's Dilemma where all parties would be better off cooperating but can't stop competing. Cold War nuclear arsenals escalated to tens of thousands of warheads far beyond rational deterrent requirements.