These are very interesting 5mm diffused RGB LEDs - instead of having 4 pins to control 3 LEDs, they have only two leads - power and ground. When powered, the LEDs perform a flashing effect with all the colors. See the video below for the timing and look. There is no way to change the 'program' or rate, its burned into a little chip that is inside the LED itself.
1 x F5 LED 5mm Flashing Rainbow Color