For example Kahoot it's background color changes really smoothly, how could I edit this script to do something like that?
while true do
wait(.25)
script.Parent.BackgroundColor3 = Color3.new(85, 0, 127)
wait(.25)
script.Parent.BackgroundColor3 = Color3.new(0, 85, 255)
wait(.25)
script.Parent.BackgroundColor3 = Color3.new(0, 170, 0)
wait(.25)
script.Parent.BackgroundColor3 = Color3.new(255, 255, 0)
wait(.25)
script.Parent.BackgroundColor3 = Color3.new(255, 85, 0)
wait(.25)
script.Parent.BackgroundColor3 = Color3.new(255, 0, 0)
end

3 comments
How about using tweenService?
TweenService can only be used on BaseParts and judging my the BackGroundColor3 property, this is on a GUI class.
Look at my screensaver. https://forum.scriptinghelpers.org/topic/188/screen-saver