How can I make a Text Button flicker black, then red non-stop?

textbutton = script.Parent --Assuming this is where it is.
waittime = .1 --How long it takes for the TextButton to change color ONCE (In Seconds)

while true do --Starts the loop.
textbutton.BackgroundColor3 = Color3.new(0, 0, 0) --Changes color to black.
wait(waittime) --Time to wait to change color.
textbutton.BackgroundColor3 = Color3.new(255, 0, 0) --Changes color to red.
wait(waittime) --Time to wait to change color again.
end --Ends the loop.

:)

@Discern Color3.new is meant to accept 3 numbers from 0 - 1, so if you want to achieve the 255 effect you should have Color3.new(255/255, 0/255, 0/255) (aka Color3.new(1, 0, 0)). Personally, this is how I'd write the code if I was doing this-

local Btn = script.Parent
local Time = .1 
local C1 = Color3.new() -- Black
local C2 = Color3.new(1, 0, 0) -- Red

while true do
    Btn.BackgroundColor3 = C1
    wait(Time)
    Btn.BackgroundColor3 = C2
    wait(Time)
end

@Discern @Ekkoh Thank you Ekkoh for clarifying that. I am just making this response because I noticed that your post was down voted and I want to make sure people realize this quirk of roblox GUIs. It is completely counter-intuitive, especially since in the properties panel of studio it displays Color3 properties with numbers ranging from 0-255, but when you edit them with a script, it must be in numbers from 0-1. As a result, I usually create this method whenever I am working with Color3 values to make it a little simpler:

local function newColor(r,g,b)
    return Color3.new(r/255,g/255,b/255)
end

frame.BackgroundColor3 = newColor(255,0,0)      --Red

It is also good to note that a quick shortcut for a black colour is to simply do this:

frame.BackgroundColor3 = Color3.new()       --Black

This works because by default it creates a Color3 object with (0,0,0) values.