It was one of those busy days in the Children's Emergency Department (ED) in December. Concerns about Group A streptococcal infections resulted in sore throats and scarlet fever being referred to ED. There was a general air of heightened anxiety among clinicians and parents. The children were happy go lucky clients. They would come in febrile and clingy. Following a dose of antipyretics and Peppa Pig, they were pleased as punch and would go home clutching presents, compliments of the season. Lurking quietly among the many febrile children would be that one child with sepsis. One had to be watchful. Amidst all this, an innocuous looking 3-week-old arrived with a history of intermittent vomiting since birth and generalised rash. He was seen by the registrar, a diagnosis of gastroesophageal reflux and cows milk protein allergy was made. The consultant reviewed the baby with the registrar. The baby's father (about 6 ft 5 in. tall) was holding a tiny incredibly alert baby with a large towel under his neck. The consultant had a fondness for babies. A quick cuddle always warms the heart especially in a busy ED setting. History was revisited again with the baby in her arms. The baby took in the proceedings with interest staring keenly at her with piercing blue eyes. He was born at term, the second child in the family. He had intermittent, small volume, non-projectile vomiting since birth. Abdominal examination was unremarkable. Hydrolysed formula and reflux medications were prescribed. The father then gave the baby a bottle. He had a small vomit, then animatedly gulped the feed, this was not quite the behaviour of a baby with reflux. The consultant watched this curious behaviour and requested a blood gas. ED became busy with an influx of febrile children, the consultant and the registrar were pulled away in different directions. An hour later, having received medications the father prepared to go home, the baby was now peacefully sleeping in his arms. He was requested to wait as the blood gas was not done as yet. The blood gas as it turned out showed hypochloremic, hypokalaemic, metabolic alkalosis suggestive of pyloric stenosis, later confirmed by ultrasound. The consultant went back to the father, apologised and explained the new plan. Father took it stoically, but expressed puzzlement. He explained that he had been feeling the baby's belly and there was no lump. Father then whipped up his shirt and showed a little scar around his umbilicus. It turned out that he had been operated for pyloric stenosis and was instructed by his mother to monitor the baby post-feed. The baby too had surgery and went home in time for Christmas. Pyloric stenosis is usually seen in infants aged 3 weeks to 3 months and can be mistaken for other conditions.1 Pyloric stenosis can run in families and a family history is a risk factor, besides this child being first born and male. The infant will usually have a period of normal feeding for the first weeks of life. However, this baby had intermittent vomiting since birth, vomiting was not forceful and the classic findings of mass abdomen and weight loss were not present. Observation in ED is as important as history and examination. The baby's feeding was the clue: there was no irritability during feeds and the voracious appetite in an alert baby was unusual. And therein lies the magic of paediatrics, there will always be the one, among many febrile children, who will come in to teach us a lesson.