The 'What's With This Sassy Lost Child?' meme originates from the popular anime and manga series One-Punch Man. The scene occurs during a meeting of S-Class heroes where the protagonist, Saitama, encounters Tatsumaki (Terrible Tornado). Despite being a powerful 28-year-old psychic, Tatsumaki's petite stature leads Saitama to mistake her for a child, prompting his iconic deadpan line. Since then, the template has become a staple for internet humor, used to mock people who act tough despite their small size or youthful appearance. It's perfectly suited for situations involving height differences, misplaced confidence, or general 'short person' energy.