1.    Import the movie in the library.

2.    Drag the movie into the timeline.  If you done this, found a good position for your fireball to start.

3.    “Press apple, shift and “Y” or go to new, layer and solid.  Then choose the colour white, press the “make comp size” and then ok

4.    Press q until finding a circle or go to tool bar to press circle.  When you found it, begin to make a circle on the screen.

5.    Use a pen by choosing the tool bar or hit “g”.  Then click four points on the circle line with the pen tool.  When it done hit “g” until finding the “convert vertex tool” or use the tool bar.

6.    Then make polygon with convert vertex tool.  When it seem right, tyre to make a squarely fire shape.

7.     Then use the convert vertex tool to smooth the fire shape.

8.    Click the white solid and hit “f” to get mask feather.  Change the mask feather pixel to 3.0.

9.    Go to the effect control, right click the mouse, go to stylize and down to glow.

10.     Change glow colour to “A & B color”.  Change white to yellow and black to red.

11.     After that keep the glow intensity out and keep the glow radius.  

12.    If the fire seems all right, then right click then mouse, go to blur & sharpen and down to fast blur then change the blurriness 0 to 5.

13.     Put the fireball where it going to start. Then go to the mask in the white solid by pressing “m” two times. That will show four different masks.    

14.      Make the fireball disappear by using the mask expansion to decrease it.

15.      Press “p” (position) after that click the stopwatch and move the fireball where it going to relies it.

16.     When fireball reach at the end.  Go to the mask and change the mask expansion to 0,which will return back the way it was.

17.      Starch the fireball out of the screen.

18.     Press “r” (rotation) click the stopwatch where fireball starts to out of the screen.

19.      Now create an adjustment layer for the background.  But put the adjustment layer at below white solid.

20.     Create a circle a round the fireball.

21.      Then go control effect, right click of the mouse, color correction and go level.

22.       Drag the right level up in the histogram with RGB.  Change the RGB to red at channel and do the same thing again dragging the level.

23.     Mask feather the whole tun until it blend and became a red glow.

24.     Do the same thing as fourteen to seventeen but move the red glow instead.

25.      When it finish click the motion blur and click the white solid and adjustment layer into motion blur as as well.

Reference: Mario Fireball TUTORIAL using Adobe After Effects