Here's the line that It says attempt to compare two userdata values
if .Parent.Bars.Thirst.Amount.Size >= UDim2.new(0,0,0,0) then local KillPlayer = game.Players.LocalPlayer.Character.Humanoid Humanoid.Health = -1 end
Instead of comparing GUI sizes, I'm pretty sure you have a IntValue or NumberValue that stores how much thirst there is. Or if you don't already add a IntValue into Amount and do this;
local TA = script.Parent:WaitForChild('Bars').Thirst.Amount.IntValue --ThirstAmount if TA.Value <= 0 then local KillPlayer = game.Players.LocalPlayer.Character.Humanoid KillPlayer.Health = 0 -- 0 Health kills player end
If this helped then please accept answer ;)