How to make NPC talk when theyre dead?

I found this script, i current killed the NPC, and it seem it didnt say what it was program to say as "Stop breaking the rules" The bottom is the script.. the error was "Chat is not a valid member of Model"

while true do
wait(0.1)
if script.Parent.Humanoid.Health < 100 then
script.Parent.Chat.Disabled = true
game:GetService("Chat"):Chat(script.Parent.Head, "Stop breaking the rules!", Enum.ChatColor.Red)
wait(2)
script.Parent.Humanoid.Health = 100
script.Parent.Chat.Disabled = false
end
end