When people see a white liquid begin to flow from a large "butterfly," many sincerely believe it's milk or some rare natural secretion. But upon closer inspection, things look quite different.
First of all, it's not a butterfly at all, but a large moth—an insect with a massive abdomen that reacts to stress in a very unusual way. When the moth senses danger, especially if someone touches its abdomen or brings water too close, its body activates a defense mechanism.
The white liquid that appears at this moment is neither milk nor a healthy product. It's a mixture of defensive substances the moth secretes to repel enemies and a urine-like liquid the insect expels when under extreme stress.
This behavior is a survival technique, designed to trick predators into thinking the prey is dangerous or spoiled.