“Plug in the USB-fan.”

These would be the famous last words of a journalist at the Singapore summit moments before their computer was compromised.

In the goody bag of treats that journalists received while covering the meeting between U.S. President Donald Trump and North Korean leader Kim Jong-Un was a seemingly harmless blue fan powered by mini USB.

How convenient. The event was high stakes. The temperature reached 91 degrees. There were press-scrums.

But experts warned that the USB powered fans could create a virtual skull and bones for anyone who plugged them in.

Experts have long warned against journalists – or anyone – plugging in free USB devices they receive at high profile events. During the G20 summit of world leaders in 2013, Russia reportedly gave delegates and foreign leaders infected USB pen drives.

But even devices found on the street can be dangerous. In 2016, a group of researchers dropped nearly 300 USB sticks at the University of Illinois Urbana-Champaign campus during a social experiment. The group did not need a long time to test the results. It took under six minutes for the first person to plug in the USB drives.

It’s unknown if any of the journalists plugged in the USB fans. But important questions remain unanswered. Do the fans work on the new line of USB-free Mac laptops? Perhaps an adapter is coming soon.