1. Pick any hero
2. Create an enemy Phoenix and level up Icarus Dive and Sun Ray
3. Move the Phoenix somewhere into the Fog of War
4. Cast Icarus Dive or Sun Ray with Phoenix

Result: The particle effects of Icarus Dive appear for you at his last known location, in this case, wherever he entered the fog. You sometimes can also see a small dot partilcle effect at his cast location. Same for Sun Ray. Upon initial cast, you see a part of the beam at his current location, then you see some yellow smoke-like particles at his last known location. Ontop of this, you also here an initial sound at his current location, and the looping sounda t his last known location.