How to make drain effect like in sewh (Something Evil Will Happen)

[TRFREMAKE (EXEC)]

Had an interest how those devs to that effect, so whenever your bar goes down it shows likely how much it drains with showing white arena on it like dis

It will fit my games so hard
Ty for help! If any info needed about what do i mean feel free to ask!

[Yarik_superpro (IMoggedOOP)]

Put frame on 1 zindex layer lower and tween it from previous health to now current.
Cache variable “previous health” somewhere outside of Healthchanged scope and in the end of healthchanged update the variable

[TRFREMAKE (EXEC)]

Thanks! Realized how to do that, I kinda use old HP Size instead of getting new and old hp which makes it a lot of times easier, just a bit of math and its done.
If anyone needs the script here it

local oldHPSize = UDim2.new(0,0,0,0)
local oldHP = 100

hum.HealthChanged:Connect(function(hp)
	if hp < oldHP then
		local bar = path --your hpbar
		local drainFrame = path --your drain Frame
		drainFrame.Transparency = 0
		oldHPSize = bar.Size
		bar.Size = UDim2.new(hum.Health/hum.MaxHealth,0,1,0)
		drainFrame.Size = UDim2.new(oldHPSize.X.Scale-bar.Size.X.Scale,0,1,0)
		drainFrame.Position = UDim2.new(bar.Size.X.Scale,0,0,0)
		game.TweenService:Create(drainFrame,TweenInfo.new(.4),{Transparency = 1}):Play()
	end
	oldHP = hp
end)

Jst correct it for a bit and it will be ok
For stamina bar im using smth like this

	local drainBar = plr.PlayerGui:WaitForChild("MainUI").PlayerUI.Bars.StaminaBar.drainFrame
	drainBar.Position = UDim2.new(bar.Size.X.Scale)
	if shift and hum.MoveDirection ~= Vector3.zero and move.stamina>0 then
		game.TweenService:Create(drainBar,TweenInfo.new(.5),{Size = UDim2.new(move.staminalosspersec/120,0,1,0)}):Play()
	else
		game.TweenService:Create(drainBar,TweenInfo.new(.5),{Size = UDim2.new(0,0,1,0)}):Play()
	end

Not gonna tell you how my movement system works, just showing yall example