"an extremely very advanced zombie with custom walk, attack and idle animation IDS I can replace within the script"

-- script for creating an advanced zombie with custom animations 
local zombie = script.Parent
local humanoid = zombie.Humanoid

local walkAnimId = "rbxassetid://your_walk_animation_id"
local attackAnimId = "rbxassetid://your_attack_animation_id"
local idleAnimId = "rbxassetid://your_idle_animation_id"

local walkAnim = humanoid:LoadAnimation(Instance.new("Animation"))
walkAnim.AnimationId = walkAnimId

local attackAnim = humanoid:LoadAnimation(Instance.new("Animation"))
attackAnim.AnimationId = attackAnimId

local idleAnim = humanoid:LoadAnimation(Instance.new("Animation"))
idleAnim.AnimationId = idleAnimId

local function playAnimation(animation, loop)
    animation:Play()
    animation.Looped = loop
end

local function stopAnimation(animation)
    animation:Stop()
end

local function onStateChanged(state)
    if state == Enum.HumanoidStateType.Walking then
        stopAnimation(idleAnim)
        playAnimation(walkAnim, true)
    elseif state == Enum.HumanoidStateType.Running then
        stopAnimation(idleAnim)
        playAnimation(walkAnim, true)
    elseif state == Enum.HumanoidStateType.Attacking then
        stopAnimation(walkAnim)
        playAnimation(attackAnim, false)
    elseif state == Enum.HumanoidStateType.Idle then
        stopAnimation(walkAnim)
        playAnimation(idleAnim, true)
    end
end

humanoid.StateChanged:Connect(onStateChanged)
playAnimation(idleAnim, true)