After reading Susan in Va's comment on the previous post, I thought, "Well, now, there ARE some more yummy little toys that you can give to your favorite child! Here, we introduce the Ebola Virus.
Yes, a virus you can cuddle with, but is resistant to antibiotics. Want something a little more...say...palatable? Try Mad Cow. Favor a more legendary plague? Maybe some Black Death is more your style.
If this is a little too adventurous for you, start with something simple like the common cold. Or maybe not a disease at all - just a small pimple you can squeeze in your sleep. At any rate, explore the Giant Microbes site for more ideas - remember, Christmas is only a few short months away!