Enable the boolprop testingcheatsenabled true code. Then, spawn the Tombstone of L(ife) and D(eath). Click "Add neighbor to family" and the choose the Grim Reaper. Click the Tombstone of L(ife) and Death and choose baby boy. Then, make the baby grow into an adult by using the tombstone.

Enter a lot then enable the boolProp testingCheatsEnabled true code. Go to the "Families" panel and select "Create A New Family". Create a male Sim and press [Shift] + N. Go to the clothing and go to "Outfits". Keep clicking the right arrow and you find two Grim Reaper outfits.