local bigHead = function(npc, maxWait)
   local head = npc:WaitForChild('Head', maxWait or 2)
   local hum = npc:WaitForChild("Humanoid", maxWait or 2)
   local neck = head and head:WaitForChild('Neck', maxWait or 2)
   if head and hum and neck then
       local old = head.Size
       local oldC0 = neck.C0
       neck.C0+= Vector3.new(0, 10, 0)
       head.Size=Vector3.new(30, 30, 30)
       head.CanCollide = false
       head.Transparency = 0.35
       local connection connection = hum.Died:Connect(function()
           connection:Disconnect()
           head.Size = old
           neck.C0 = oldC0
       end)
   end
end

workspace.Npcs.ChildAdded:Connect(bigHead)

for _, npc in next, workspace.Npcs:GetChildren() do
   bigHead(npc, 1e-100)
end