Im not sure what you're getting at, but...
If I'm correct (98% sure

) then sprites cant be disabled. They are litterally graphics in the game and nothing more. If you want the trick where a marine or ghost is invisible and is shooting at nothing over and over then do this:
You can use whatever editor thats has triggers and locations. (Xtra, SF, or SCMD2)
Have 1 location named (lets say) "InvisibleShootingMan 1".
Then have a trigger like this:
| Trigger |
| Description: |
| Invisible Shooting Man |
|
| Players: |
| ¤ Whatever player the shooting man is. |
| Conditions: |
¤ Always
|
¤ -OR-
|
| ¤ Whatever condition you want here. |
| Actions: |
| ¤ Set doodad state: 'Disable' doodad state for 'unit' at location 'InvisibleShootingMan 1'. |
Not all units will do the shooting man thing though so only use marines or ghosts (thats all I know about anyways

). I hope thats what you were looking for. If not, then please refrase the question or show me the map you saw it in.