Zombie manager example

--zombie manager
--put all zombies into workspace.Zombies
--to add new zombies, just insert humanoids into workspace.Zombies

local zombies={}
local zombieRange=50

function moveZombie(zombie,location)
    zombie.Humanoid:MoveTo(location) -- MoveTo no longer requires a part as an argument
end

function unregisterZombie(zombie)
    for i,v in pairs(zombies) do
        if v==zombie then
            table.remove(zombies,i)
            break
        end
    end
end

function registerZombie(zombie) -- add a new zombie
    assert(zombie:FindFirstChild("Humanoid")~=nil,"Zombie does not have a humanoid.") -- this line makes sure it has a humanoid
    assert(zombie:FindFirstChild("Torso")~=nil,"Zombies does not have a torso.") -- similar to above
    zombie.Humanoid.Died:connect(function()
        unregisterZombie(zombie) -- remove this zombie from the list because it died
    end)
    zombies[#zombies+1]=zombie
end

for i,v in pairs(workspace.Zombies:GetChildren()) do
    registerZombie(v)
end
workspace.Zombies.ChildAdded:connect(registerZombie)
workspace.Zombies.ChildRemoved:connect(unregisterZombie)

--main loop
while wait(0.1) do --change 0.1 to something higher if you're having lag caused by this script
    for _,zombie in pairs(zombies) do
        if not zombie:FindFirstChild("Torso") or not zombie:FindFirstChild("Humanoid") then --if the torso or humanoid was somehow removed :(
            unregisterZombie(zombie)
        else
            local zombiePos=zombie.Torso.Position
            local nearestPlayerPos
            local nearestDistance=zombieRange
            for _,plr in pairs(game.Players:GetChildren()) do
                if plr.Character and plr.Character:FindFirstChild("Torso") then
                    local playerPos=plr.Character.Torso.Position
                    if (playerPos-zombiePos).magnitude<=nearestDistance then
                        nearestPlayerPos=playerPos
                        nearestDistance=(playerPos-zombiePos).magnitude
                    end
                end
            end
            if nearestPlayerPos then -- if a player was found near enough to the zombie
                moveZombie(zombie,nearestPlayerPos)
            end
        end
    end
end