You always suspected they were mutants. Now you have proof.
The oozing from every orifice. The bizarre speech pattern. The insatiable hunger for sour gummy candies. You'd had your suspicions for a long time that this was less child than creature. But those suspicions have now been confirmed.
The feet! Dear God, the feet! Light, breathable, flexible. So unlike any human child feet you've ever seen. Some will say, "Don't be silly. Those are just Vibram Alitza shoes," and at first glance, they're pretty convincing. But one very unique feature tipped you off. No, not the wet traction. You've seen normal children scale jungle gyms like a spider monkeys on a rainy day.
If there's one thing you know about human kids, it's that if you want them to do something, you have to ask them over and over before they comply. The high responsiveness of these shoes? Dead giveaway.