The Birds, the Bees and the Platypuses

Michael Gross has been writing about science full time for the last eight years and as a night time hobby for the previous seven. From his treasure troves, he now presents his favourite science stories from these 15 years.
What are the attractions that make him revisit a topic or reread an article again and again? Often, it's the sheer craziness of wildly unexpected findings or grotesquely oversiz...