Activation Tracks allow for the enabling and disabling of game objects during “Timeline Sequencing”.
To add an Activation Track to your Timeline editor, just right-click within the lefthand side and select “Activation Track”.
Notice how there is a new section for a Game Object reference available now. You can drag and drop the game object that you want to activate/deactivate into this reference.
You’ll see that the new track also has a clip highlighted area in green that says “Active”. For the length of that bar, the referenced object will be set to active. If the clip extends the full length of the track, then the object will just remain active. If you shorten the length of this then once the sequencing passes the end of the “Activation Clip” then it will deactivate the object.
You can also add multiple iterations of the Activation Clips to turn the objects off and on repeatedly by right-clicking and selecting “Add Activation Clip”.