PLEASE READ BEFORE WATCHING THIS VIDEO!
First of all, you cannot do this cheat if you don't have World Adventures. I have gotten messages from people telling me they can't do the cheat . . . and have found out afterwards that all of them didn't have the expansion pack. Obviously, you CAN'T DO THIS CHEAT WITHOUT WORLD ADVENTURES. You can't even make a mummy without the expansion pack.
Make sure you keep your sim in the sarcophagus for longer than just an hour. Keep him there for a night, or, if you use the testingcheatsenabled true cheat you can keep him in there for a whole day or more by keeping all his vital stats up except for his energy stat. If his athletic skill is not increasing while he is there then the tomb is somehow not working for your sim. (Maybe if they have the lucky trait they can't become mummies, but I haven't experimented with that yet.) While they are in the sarcophagus get their athletic level up to at least a three and eventually they will become a mummy. If messages appear after a normal looking sim comes out of the coffin saying "Sim so-and-so feels strong but weird about the sarcophagus" then you are doing it right and just keep trying.
Answers to some common questions:
Yes, you can make teen mummies.
Yes, you can make mummy ghosts.
Mummies can't have children.
You cannot make mummy children.
You can find the sarcophagus fragments by searching the tombs.
You need testingcheatsenabled true in order to use the buydebug cheat.
Testingcheatsenabled true will NOT harm your game. Just don't use too many crazy cheats at once because if you give the game too many tasks at the same time it will crash. Take it slow while you cheat.
You can make female mummies.
Mummies don't have to sleep or use the bathroom, but they need everything else. Unlike ghosts, they can die. (which is funny because they're already dead.)
Mummies jog the way they walk.
For those of you who did not understand my brilliant sense of humor, the black sarcophagus curses you while the gold one cures you.
Sometimes there is a glitch where after your mummy becomes human again he still walks like a mummy. In neighborhood mode evict your sim and move him back to the house. Sometimes that resets your sim. I use this method for most of the strange glitches that occur while playing the game.
Link to "Simhotep" on the Sims 3 Exchange: http://www.thesims3.com/assetDetail.h...