The Sting is the Kha'ak light missile.
This is a fast missile that will explode near the target ship. It has a deadly power against all light fighter ships. It is mostly found in Kha'ak Scouts.
This munition is fast and does a reasonable about of damage, making it a serious threat to any Scout and some interceptors that cannot outrun it. However, like much of the Kha'ak arsenal, it no longer poses the same threat it once did in X3: Reunion: most M5s can easily dodge it or outrun it.