Where i need to change humanoid on zombie?

Hello everyone, I have problem with script in gun. I want to change humanoid on zombie, becouse monsters hitting other monsters, so it's anoying. When i change in monster humanoid on zombie - i can't hurt them... It's not my script. Weapon created by WIJ. It's not all script, becouse max characters are 10,000, but i think in these lines. Here is script, if someone can show/write me where should i change :

------------------------------------------------------------------------------------Raycasting functions
 function raycast(startp, endp, ign)
    local vec=(endp-startp)
    if vec.magnitude<1000 then
    local hit,pos=game.Workspace:FindPartOnRay(Ray.new(startp,vec),ign)
    if hit and pos then
        if hit.Parent.className=="Tool" or hit.Parent.className=="Hat" then
            if hit.Parent.Parent ~= nil then
            if hit.Parent.Parent:findFirstChild("Humanoid")~=nil then
            return hit.Parent, pos
            end
            end
        elseif string.lower(hit.Name)=="glass" then
            local vec=(endp-pos)
            hit,pos=raycast(pos,vec,ign)
        elseif string.lower(hit.Name)=="water" then
            local vec=(endp-pos)
            hit,pos=raycast(pos,vec,ign)
        elseif hit.Transparency==1 or hit.Name=="Bullet" or hit.Name=="BulletTexture" then
            local vec=(endp-pos)
            hit,pos=raycast(pos,vec,hit)
        end
    end
    return hit,pos
    end
    return nil
end
-------------------------------------------------------------------------------






function tagHumanoid(humanoid)
    local plr=game.Players:playerFromCharacter(sp.Parent)
    if plr~=nil then
        local tag=Instance.new("ObjectValue")
        tag.Value=plr
        tag.Name="creator"
        tag.Parent=humanoid
        delay(2,function()
            if tag~=nil then
                tag.Parent=nil
            end
        end)
    end
end

function onKeyDown(key,mouse)
    key=key:lower()
    --[[if key=="r" and not reloading then
        reload(mouse)
    end]]
end

function movecframe(p,pos)
    p.Parent=game.Lighting
    p.Position=pos
    p.Parent=game.Workspace
end


function checkAllyWIJ(killer, victim)
if game:findFirstChild("Teams")~=nil then
    if killer ~= victim then
        if killer.TeamColor==BrickColor.new("Bright blue") and victim.TeamColor==BrickColor.new("Bright green") then 
        return true
        elseif killer.TeamColor==BrickColor.new("Bright green") and victim.TeamColor==BrickColor.new("Bright blue") then
        return true
        elseif killer.TeamColor == victim.TeamColor then
        return true
        else
        return false
        end
        return false
    else
    return true
    end
    return false
else
return false
end
end

function takeDamage(dm, pl)
if pl:findFirstChild("Shield")~=nil then
sh=pl:findFirstChild("Shield")
    if sh.Value==0 then
    pl.Humanoid:TakeDamage(dm)
    elseif sh.Value<dm then
    newdm=dm-sh.Value
    sh.Value=0
    pl.Humanoid:TakeDamage(newdm)
    elseif sh.Value>dm then
    sh.Value=sh.Value-dm
    elseif sh.Value==dm then
    sh.Value=0
    end
else
pl.Humanoid:TakeDamage(dm)
end
end

function fire(aim)
    script.Parent.Handle.Fire.Pitch=(math.random(-5,-1)/10)+1
    sp.Handle.Fire:Play()

    local bullet=Bullet:clone()
    --[[local bt2=game.Lighting.BulletTexture:clone()
    bt2.BrickColor=BrickColor.new("Bright red")
    bt2.Mesh.Scale=Vector3.new(.5,.5,2)]]--
    local totalDist=0
    Lengthdist=-RayLength/.5
    local startpoint=sp.Handle.CFrame*BarrlePos
    local direction=(aim-startpoint)
    local cfrm=CFrame.new(startpoint, direction+startpoint)
    local vector=startpoint+(direction.Unit*999)
        if (startpoint-vector).magnitude<1000 then
            if game.Workspace:FindPartOnRay(Ray.new(player.Character.Head.Position,startpoint-player.Character.Head.Position),player.Character)==nil then
            local hit,pos=raycast(startpoint,vector,player.Character)
            bullet.Parent=game.Workspace
            --bt2.Parent=game.Workspace
            if hit~=nil then
                if hit.Parent:FindFirstChild("VecHealth")~=nil then
                vech=hit.Parent:FindFirstChild("VecHealth")
                vech.Value=vech.Value-VehicleDamage
                end
                if hit.Parent:FindFirstChild("HealthStatus")~=nil then
                fo=hit.Parent:FindFirstChild("HealthStatus")
                fo.Value=fo.Value-BaseDamage
                end
                local humanoid=hit.Parent:FindFirstChild("Humanoid")
                if humanoid~=nil then
                    local damage=math.random(BaseDamage-(BaseDamage*.25),BaseDamage+(BaseDamage*.25))
                    if hit.Name=="Head" then
                        damage=damage*1.25
                    elseif hit.Name=="Torso" then
                    else
                        damage=damage*.75
                    end
                    if humanoid.Health>0 then
                        local eplr=game.Players:playerFromCharacter(humanoid.Parent)
                        local plr=game.Players:playerFromCharacter(sp.Parent)
                        if eplr~=nil and plr~=nil then
                        if (checkAllyWIJ(plr, eplr)==false) then
                                if hit.Parent:findFirstChild("ForceField")==nil then
                                tagHumanoid(humanoid)
                                takeDamage(damage, humanoid.Parent)
                                sX=sfx:clone()
                                sX.Parent=player
                                sX:play()
                                end
                        end
                        else
                            if hit.Parent:findFirstChild("ForceField")==nil then
                            tagHumanoid(humanoid)
                            takeDamage(damage, humanoid.Parent)
                            sX=sfx:clone()
                            sX.Parent=player
                            sX:play()
                            end
                        end
                    end
                end
                distance=(startpoint-pos).magnitude
                bullet.CFrame=cfrm*CFrame.new(0,0,-distance/2)
                bullet.Mesh.Scale=Vector3.new(.15,.15,distance)
            else
                bullet.CFrame=cfrm*CFrame.new(0,0,-RayLength/2) 
                bullet.Mesh.Scale=Vector3.new(.15,.15,RayLength)
            end
            if pos~=nil then
                --bt2.CFrame=bullet.CFrame
                --movecframe(bt2,pos)
            end
            local deb=game:FindFirstChild("Debris")
            if deb==nil then
                local debris=Instance.new("Debris")
                debris.Parent=game
            end
            check()
            game.Debris:AddItem(bullet,.05)
            game.Debris:AddItem(sX, .3)
            --game.Debris:AddItem(bt2,.5)
        end
    end
end

function onButton1Up(mouse)
    down=false
end

function onButton1Down(mouse)
    h=sp.Parent:FindFirstChild("Humanoid")
    if not enabled or reloading or down or h==nil then
        return
    end
    if Charge.Value<MaxCharge and h.Health>0 and overheated==false and battery==true then
        --[[if sp.Ammo.Value<=0 then
            if not reloading then
                reload(mouse)
            end
            return
        end]]
        down=true
        enabled=false
        while down do
            if Charge.Value>=MaxCharge or sp.Parent:FindFirstChild("Humanoid")==nil or overheated == true then
                break
            end
            sfd=sfd+1
            if sfd>=shotsForDepl then
            sfd=0
            batteryLife.Value=batteryLife.Value-math.random(minDepletion, maxDepletion)
            end
            if burst then
                local startpoint=sp.Handle.CFrame*BarrlePos
                local mag=(mouse.Hit.p-startpoint).magnitude
                local rndm=Vector3.new(math.random(-(Spread/10)*mag,(Spread/10)*mag),math.random(-(Spread/10)*mag,(Spread/10)*mag),math.random(-(Spread/10)*mag,(Spread/10)*mag))
                fire(mouse.Hit.p+rndm)
                Charge.Value=Charge.Value+math.random(chargeperfireMIN, chargeperfireMAX)
                if Charge.Value>=MaxCharge then
                    break
                end
                wait(.05)
                local startpoint=sp.Handle.CFrame*BarrlePos
                local mag2=((mouse.Hit.p+rndm)-startpoint).magnitude
                local rndm2=Vector3.new(math.random(-(.1/10)*mag2,(.1/10)*mag2),math.random(-(.1/10)*mag2,(.1/10)*mag2),math.random(-(.1/10)*mag2,(.1/10)*mag2))
                fire(mouse.Hit.p+rndm+rndm2)
                Charge.Value=Charge.Value+math.random(chargeperfireMIN, chargeperfireMAX)
                if Charge.Value>=MaxCharge then
                    break
                end
                wait(.05)
                fire(mouse.Hit.p+rndm+rndm2+rndm2)
                Charge.Value=Charge.Value+math.random(chargeperfireMIN, chargeperfireMAX)
            elseif shot then
                Charge.Value=Charge.Value+math.random(chargeperfireMIN, chargeperfireMAX)
                local startpoint=sp.Handle.CFrame*BarrlePos
                local mag=(mouse.Hit.p-startpoint).magnitude
                local rndm=Vector3.new(math.random(-(Spread/10)*mag,(Spread/10)*mag),math.random(-(Spread/10)*mag,(Spread/10)*mag),math.random(-(Spread/10)*mag,(Spread/10)*mag))
                fire(mouse.Hit.p+rndm)
                local mag2=((mouse.Hit.p+rndm)-startpoint).magnitude
                local rndm2=Vector3.new(math.random(-(.2/10)*mag2,(.2/10)*mag2),math.random(-(.2/10)*mag2,(.2/10)*mag2),math.random(-(.2/10)*mag2,(.2/10)*mag2))
                fire(mouse.Hit.p+rndm+rndm2)
                local rndm3=Vector3.new(math.random(-(.2/10)*mag2,(.2/10)*mag2),math.random(-(.2/10)*mag2,(.2/10)*mag2),math.random(-(.2/10)*mag2,(.2/10)*mag2))
                fire(mouse.Hit.p+rndm+rndm3)
                local rndm4=Vector3.new(math.random(-(.2/10)*mag2,(.2/10)*mag2),math.random(-(.2/10)*mag2,(.2/10)*mag2),math.random(-(.2/10)*mag2,(.2/10)*mag2))
                fire(mouse.Hit.p+rndm+rndm4)
            else
                Charge.Value=Charge.Value+math.random(chargeperfireMIN, chargeperfireMAX)
                local startpoint=sp.Handle.CFrame*BarrlePos         
                local mag=(mouse.Hit.p-startpoint).magnitude
                local rndm=Vector3.new(math.random(-(Spread/10)*mag,(Spread/10)*mag),math.random(-(Spread/10)*mag,(Spread/10)*mag),math.random(-(Spread/10)*mag,(Spread/10)*mag))
                fire(mouse.Hit.p+rndm)
            end

            wait(Firerate)
            if not automatic or battery==false then
                break
            end
            if down==true then
            wait(.06)
            end
        end 
        enabled=true
    else
        sp.Handle.Trigger:Play()
    end
end

function onEquippedLocal(mouse)
    if mouse==nil then
        print("Mouse not found")
        return 
    end
    script.GunGui:clone().Parent=player.PlayerGui
    mouse.Icon=Cursors[1]
    mouse.KeyDown:connect(function(key) onKeyDown(key,mouse) end)
    mouse.Button1Down:connect(function() onButton1Down(mouse) end)
    mouse.Button1Up:connect(function() onButton1Up(mouse) end)
    equiped=true
    down=false
    check()
end
function onUnequippedLocal(mouse)
        if player.PlayerGui:FindFirstChild("GunGui")~=nil then
        player.PlayerGui:FindFirstChild("GunGui").Parent=nil    
        end
    equiped=false
    reloading=false
    down=false
    sp.Name = OriginalToolName
end
sp.Equipped:connect(onEquippedLocal)
sp.Unequipped:connect(onUnequippedLocal)
check()