local plr = game.Players.LocalPlayer.Character while true do script.Parent:TweenSize(UDim2.new(plr.Humanoid.Health/plr.Humanoid.MaxHealth, 0, 1, 0), Enum.EasingDirection.Out, Enum.EasingStyle.Linear, 0.1) wait(0.1) end
and the error it gives is
Humanoid is not a valid member of Model

2 comments
still Humanoid is not a valid member of Model
Then the person is dead or you have a script deleting it.