I am not sure which game you are talking about, but I have played many dbz games, and I don't know that you can get a dead goku (otherworldly goku) in any game. Sorry.
Well theres one game that u can get Goku with halo which is Dragon ball z budokai Tenkaichi 3
( if that's the game u hav ) U will need to buy it on z item thing (its called Halo).
then after u bought equip it to any character
u cant lol im not sure