RAYHOME LED Sign for Car, 7''x3''Flexible LED Matrix Panel USB 5V Bluetooth Application Control DIY Programmable Scrolling LED Sign for Car Party Wedding Festival

I'm going to guess it was something along the lines of this [0]... wow now I kind of want to buy one of their larger versions for the back of my car to remind tailgaters "Yes I CAN go even slower" when I'm already going 5-10mph over the speed limit

[0] https://amzn.to/3GiMXaA