Run it
Copy the script and paste it into your executor.
for _, item in pairs(workspace:GetDescendants()) do
if item:IsA("Humanoid") then
local highlight = Instance.new("Highlight")
local parent = item.Parent
if parent then
local plr = game.Players:GetPlayerFromCharacter(parent)
if not plr then
highlight.Parent = parent
end
end
end
endHighlights all NPCs in the game!

Universal