Grand Theft Auto V resident berdu captures a Reaper creepily hovering over Los Santos, thanks to a new mod that infuses a little Mass Effect into Rockstar's game.
JJxORACLE created the mod, though it's currently in beta. It replaces the blimp currently floating around the game. The Reaper doesn't have any collision detection, though, so you'll pass right through it and sometimes it will disappear entirely.
People are already coming up with some excellent ideas for JJxORACLE to play with, too.