example.lua

local name, count
for name in pairs(minetest.luaentities) do
    if name = "mobname" then -- Replace mobname with the name of the mob
        count = count + 1
    end
end
if count >= mobcap then return end -- Replace mobcap with the number of mobs at a time.

Small error:
if name = "mobname" then -- Replace mobname with the name of the mob
should be:
if name == "mobname" then -- Replace mobname with the name of the mob

Thank you for the help: AntumMT/mod-sneeker@d336800