How do I change a selection box's color?

p = script.Parent
s = p.SelectionBox
k = p.Kill

while true do
    s.Color = BrickColor.new("Bright blue")
    p.BrickColor = BrickColor.new("Bright blue")
    k.Disabled = true
        wait(5)
    s.Color = BrickColor.new("Bright red")
    p.BrickColor = BrickColor.new("Bright red")
    k.Disbaled = false
        wait(5)
end

Nothing happens in-game. How do I make it work? I've already checked the wiki, and that's how it said to do it.