Smartphone users in Hawaii were alerted with this warning on Saturday: "Ballistic missile threat inbound to Hawaii. Seek immediate shelter. This is not a drill."
Understandably, the reaction was a collective sense of panic.
Fortunately, the warning was a mistake inadvertently sent by a careless employee at Hawaii's Emergency Management Agency (EMA), but the hysteria was already set in motion.
It took 18 minutes for officials to announce the blunder via email, but it still took 38 minutes for any kind of followup text to be sent to mobile phone users.
Many residents feared for their lives as they braced themselves for an end that wouldn't come.
A visitor from the UK, Emma Hine, recalled the harrowing moment to BBC.
It was one of the worst experiences because I actually thought we were going to die. I've got a daughter - Chloe - back home in the UK and I thought 'I'm not going to get a chance to say goodbye'. Everyone was genuinely terrified.