magnetisum:like an aura but whenever an enemy unit atacks one of your units inside that aura the atack projectille is drawn towards the hero and the hero takes the damage and any other effects like envenomed weapons instead of the other unit
another version of magetisum:like magnetisum but you target a unit and the projectile are drawn towerds the target unit and they take the damage and effects insted of the origanaly atacked units
There is no known way to manipulate missles after they have been thrown via triggers. However, most attacks have homing. You might be able to do something with that and dummy units...
homing? Umm... what do you mean by that Raven? Anyway, this spell indeed sounds pretty impossible, atleast with what I know by now. My JASS experience is very poor (4 days by now...) and I know little things to do with it. But if Raven says that it's impossible, it must be. He obviously knows much more JASS than me...
Homing. If an archer fires an arrow at a footman, but before the arrow hits, the footman is teleported across the map, the arrow will follow the footman will out of range.
btw, also if u disable the "homing missile" field in object editor, the attacked unit takes damage ...the only way i could solve this problem is changeing the attack to siege