Introduction: Tamagotchi Cake. This is my Tamagotchi cake, based on the first generation that came out when I was in 7th grade!
I still love Tamagotchi and I always will.  My very first one (which I still have) is purple with the pink zig-zag border.  I meant to make that color for my cake, but I opened up my bucket of fondant to see that it was blue!  So I had to improvise.  :)
I wanted to save this cake, and not eat it, so I made it from a "cake dummy", which is foam, covered and decorated as you would decorate a real - baked cake.  If you follow my instructions, the only thing you have to sub out would be the Styrofoam for real cake, layer it and carve it with a serrated knife to your tama-shape!
This Tamagotchi Cake features blue and green fondant, starburst buttons, a sugar glass screen, backed by airbrushed rice paper and the character and functions were hand-drawn with an edible ink.  (Ball chain is real, so don't eat it.)  This thing makes me want to hoist it over my shoulder and play those cute beeping noises to rep my generation.  (I don't have a boombox.)   Step 1: Materials!. I am going to try and name everything!
- cake or foam
- fondant (2 colors)
- starburst or fondant for your buttons
- food color paste to dye fondant if needed
- sugar, lite corn syrup, water to make sugar glass
- rice paper
- airbrush (i used my mom's) or you can hand draw on rice paper
- knife and stove flame to heat the knife and cut candy glass
- random fondant tools or improvised , ie . skewer
- black edible ink marker (cake shop)
- skewers to hold your foam together if you make a dummy version
- wire and ball chain to add the effect of a real tama
- patience!! Step 2: Making Your Dummy.. I bought these three shapes from the dollar store, put them together and knife-traced my shape.  From that point, I used a sharp knife to saw away the big chunks, and I carefully shaved the edges that I wanted smoother.  
I stuck skewers throughout the pieces, to hold them together as one piece, ultimately.  I chose to go in different directions to cause variation for a better hold.  Stick the skewers in most of the way, break it off carefully and leave a small piece at the end.  I used a hammer to get rid of the excess and to push it into the foam the rest of the way.
Once it's all in one piece, you can use your knife to saw, sculpt and shape it the way you'd like.  (the fine edges and soft curves) This will also help the 3 pieced become one.  
Now, if you have a cake, you can give a light layer of icing, or a "crumb coat" I believe.  But in this case, I used a spatula and piping gel - a clear gooey glue, edible, to help the fondant adhere in the next step. Step 3: Cover Your Cake.. My purple is totally blue.  lol.
Now it's time to get your main color, knead it a while so it becomes a little soft.  Then use a fondant roller or a clean rolling pin to use pressure and roll out the fondant so that it's thin, but not too thin.  You don't want it to tear.  Most importantly, you can't fix this step, so you want to make sure that you have enough, and you roll it out wide enough to cover your cake.  It's okay to have too much, but it's a tragedy to have too little.  :)
Carefully transfer your fondant to your cake, use your soft fingertips to press and smoothen out the top, no air bubbles!!  Then walk your way over the edge of the cake on top, and go around, edge your way lower, and walk it around.  You have to go tiny bit, by tiny bit, all the way around.  Don't skip ahead or you will be caught in some nasty folds and you will mess your fondant up.
By the time you reach the bottom, you will be proud of yourself because those scary folds don't matter anymore for your awkward shape!! :D  Then trim the excess and smoothen your edges. Step 4: Make Your Screen.. This is the horrible, wonderful, fun, painful, bleeding cuts, innovative, skilled step. 
My first time making candy glass and it was a pain in the booty.  I don't know how those 10 year old boys do it on youtube!  BS. lol.  So, I mixed 3 cups sugar, 1 cup light corn syrup, 1 cup water and slowly boiled it to 290 degrees.  I turned up the heat at one point and that's probably why my glass turned yellow.  But that's okay, because the airbrushed colors on my rice paper, they made it look like an old tamagotchi screen.  So it's all good.  ;)
Basically, find your preferred recipe and method for making sugar glass and follow it perfectly.  :)  I tried.  
After your glass sets up, put it on wax paper.  
Get your rice paper, cut to a template size that you'd like, airbrush, color or do nothing to it, for your desired look of an "under screen".  The layered effect is awesome!!
Once your rice paper is ready, lay it face down onto the glass and make sure you have no air pockets.  Adhere it really well by pressing it carefully.
As per the Dexter Slide Candy Instructable (thank you!), heat up an ugly knife and ASAP slice your candy glass around your rice paper.  CAREFULLY.  
Eventually, your screen will be cut and ready!
Next, use an edible ink, and make the function icons freehand.  Try not to mess up because it's a pain if you do! lol.  (I'm assuming it would be.)
After your icons are ready, figure your spacing and make your tamagotchi!!  I chose a side view of Tarakotchi.  Sketch him out in the strange/gummy/sticky candy glass and try to make him look pixelated. Step 5: Ziggy Zaggy!. Make your white fondant into the color you desire, or find fondant already colored.  :)  My aunt gave me the color paste colors from Williams Sonoma and I think they are the best option for coloring fondant because they are a thick consistency, less liquid.
Roll your fondant out, big enough to make a shape around your screen.  Put your screen on top, trace-cut around it, take screen off, remove the square, put it away to use some other time.  Next, cut your zig zags and make sure that your screen-frame will still fit on your tamagotchi.  This will take patience and ... trickiness.  I used an exacto, only purposed for food, to clean up and shave rough edges.   Step 6: Buttons. Now, open those starburst and knead them in your fingers as tough as possible to let your body heat soften them up.  I got two buttons out of one starburst.  Place them where you'd like them to show!
You can use piping gel to adhere your screen and buttons to the cake.  :) Step 7: Humongo Ball Chain As a Finishing Touch!. I went to Ace Hardware and picked out the biggest ball chain they had.  I made it 1.5 feet long and I bought the coupler thingy to close the chain.  
I got a piece of wire with ... 2 long sides, so that I could stab it into the cake, fondant and foam to anchor it.  It worked!!
Just make sure you position your ball chain where you want it (in terms of the closure piece) because you won't be able to move it afterward.  :)
Now that your tamagotchi cake is done, display it however you'd like and eat it if it's real!  I put mine on a jean jacket which was forced upon me as a child, so I had to include it ;) hahah.  
********* Bandai, if you see this - I'd really love a Tamagotchi iD, color screen tamagotchi! <3  ************