Fighting With Your Guts
When threatened, sea cucumbers expel their internal organs. Their digestive systems contain poisonous acids and enzymes that repel predators, and even sometimes kill them. Sea cucumbers occasionally lose their entire digestive systems to this gut-expulsion, but the organs grow back quickly.
We All Make Mistakes
Tim Berners-Lee, the man who invented the main software for the World Wide Web, doesn't love his creation. He doesn't think that adding "//" after "https:" was necessary. It was standard for coding at the time, but it never really served a purpose. He believes that leaving it out would have made the internet a simpler place.