There are situations when you want some objects to appear or disappear in your 3d animations. This post will help you understand how the visible key in an animations works. This technique usually looks wonderful on text animations in your introduction videos and simple title animations.
1) Create a new scene and import all xmas color bulbs
2) Place the bulbs in a row
3) Select each bulb one by one and set the visible key for all the bulbs except the last blue one, in the first frame as OFF.
4) Now go to frame 11 and switch OFF the visibility for the blue ball and switch ON the visibility for yellow bulb.
5) Now switch OFF the yellow bulb and switch ON the Next one in the row. Continue this for every 11 frames in the animations until you reach the last bulb
After you complete this, you should be on frame 51 or more. Now play the animation to see the like a running light sequence. The exported video is attached below. You can apply the same idea on different animation to see such effects.