Online ad firm Traffix is being sued by 50 Cent over a promotional game called Shoot the Rapper.
The musician, himself a shooting victim, alleges that the game illegally uses his image and encourages users to target him.
According to the BBC, he is suing the New York-based firm for $1m (£486,000).
The ad invites users to “shoot the rapper” and win a cash prize or ringtones, the lawsuit says.
If they hit him, the screen goes red and the user is redirected to Traffix’s site.
50 Cent’s lawyer Peter Raymond said the game used his likeness without permission, adding that "it looks like him, and there's no doubt the character is intended to be him".
Traffix is yet to comment.