Hi AZEKIALDUTTON009 You should be able to do this without needing a radius sprite. You can add the move to behavior to your heat sink missile and set an event for every tick move to enemy. By default the angle will set toward it too.
Now if you wanted to make a heat sink missile where its chasing the enemy but you can cause it to chase something else (distracting it) like in movies that can be done too. Let me know if you want more info on that.