I replaced the incandescent bulb in a dollar store pumpkin with a slow flash RGB LED. The LED uses a chip contained within the epoxy therefore no dropping resistor is needed. It uses two AAA batteries’ so the blue stops working after the batteries voltage has dropped too much. The incandescent bulb actually flashes too. It uses a bimetallic strip that when heated opens the circuit. Mathematical! Two completely different ways to make a light blink!
Here’s a video that shows the color transitions.