Head lice. For many parents it feels like a constant battle, and there's no question who's winning.
Head lice have had a long time to perfect their survival strategy, after all. The earliest recordings of lice are from Ancient Eygpt, where they were found on mummies, and head lice combs buried in tombs.
Head lice can survive under water for several hours. They attach themselves to your scalp with glue. They can even change their colour as camoflague depending on the colour hair they're in. These critters are next-level battle strategists. But you can be smarter.