local zombie = script.Parent
local humanoid = zombie:FindFirstChildOfClass("Humanoid")

if not humanoid then
    warn("No Humanoid found in the Zombie")
    return
end

local billboardGui = zombie:FindFirstChild("BillboardGui")
if not billboardGui then
    billboardGui = Instance.new("BillboardGui")
    billboardGui.Name = "BillboardGui"
    billboardGui.Size = UDim2.new(0, 200, 0, 50)
    billboardGui.Adornee = zombie
    billboardGui.Parent = zombie
end

local healthBar = billboardGui:FindFirstChild("HealthBar")
if not healthBar then
    healthBar = Instance.new("Frame")
    healthBar.Name = "HealthBar"
    healthBar.Size = UDim2.new(1, 0, 1, 0)
    healthBar.BackgroundColor3 = Color3.new(0, 1, 0)
    healthBar.Parent = billboardGui
end

local function updateHealthBar()
    local healthPercentage = humanoid.Health / humanoid.MaxHealth
    healthBar.Size = UDim2.new(healthPercentage, 0, 1, 0)
    healthBar.BackgroundColor3 = Color3.fromRGB(
        255 * (1 - healthPercentage),
        255 * healthPercentage,
        0
    )
end

while true do
    updateHealthBar()
    wait(1)
end