My script does not work. What did I do wrong?

Before you act like "You put in x but don't understand x? Well I got some stuff from a tutorial on the Dev hub and the rest I made myself. Whenever I put in the chat "spoopy" it doesn't work. What am I doing wrong"?

local announcer = Instance.new("Message")
local function Joined(plr)
	-- Everytime they chat, we want to know
	plr.Chatted:Connect(function(msg)
		if msg == "spoopy" then -- Aha, that's our cue
			game.Lighting.Theboss:clone().Parent = game.Workspace
			announcer.Parent = game.Workspace
			announcer.Text = "Uh oh someone summoned something weird!"
			wait(3)
			announcer:remove()
		end
	end)
end

remove and message is deprecated, so is hint in case you saw that somewhere. Also you didn't call Joined.

local announcer = Instance.new("Message")
local function Joined(plr)
    -- Everytime they chat, we want to know
    plr.Chatted:Connect(function(msg)
        if msg == "spoopy" then -- Aha, that's our cue
            game.Lighting.Theboss:clone().Parent = game.Workspace
            announcer.Parent = game.Workspace
            announcer.Text = "Uh oh someone summoned something weird!"
            wait(3)
            announcer:remove()
        end
    end)
end

game.Players.PlayedAdded:Connect(function(p)
	Joined(p)
end)

I would replace the message with prints so you can see them in the output.

local function Joined(plr)
    -- Everytime they chat, we want to know
    plr.Chatted:Connect(function(msg)
        if msg == "spoopy" then -- Aha, that's our cue
            game.Lighting.Theboss:clone().Parent = game.Workspace
            print("Uh oh someone summoned something weird!")
        end
    end)
end

game.Players.PlayedAdded:Connect(function(p)
	Joined(p)
end)

If this helps then please click the Accept button, if it doesn't, write in the comments, Enjoy!