After you reach level 10 or it could be as early as level 8 you will eventually get an opportunity to create something from the science department at the hospital. You will see the science symbols in the message so watch for that. You will have to create or find a few different objects such as a pink diamond and you have to get it cut into a heart shape, you have to find a certain gem or rock and I think you have to grow life fruit. I think any 10 fruits are fine, meaning they don't have to be perfect (not sure). After you have given the science lab all your items you will be given something and you have to use inventing to use that something to make a simbot. Then, you can name it. It has to eat and sleep just like a sim which stinks and it can smash items which is cool but other than that it's just does some robot type things when it's not doing anything and if it gets wet it shorts out and you have to repair it. That's the closest you get to having it die. When you create it though you have the option to keep it or release it into the wild but once you have it you're stuck with it.
Good luck.
