I have a png sequence attached on the game object.it has a sphere collider.when the other enemy game object collide with it i want that the png sequence run according to the position of the enemy game object.how can i find the angle between these 2 game objects???i know how to run the png sequence.

To find the angle between two vectors, you can use the dot product:

It will give you the cosine of the angle between the two vectors multiplied by the two magnitudes of the vectors. So if you normalize the two vectors before multiplying, you will get exactly the cosine of the angle.