Donut may seem like a rather innocuous and tasty user, but you underestimate the lengths people will go to to get him. Simply place Donut in plain sight surrounded by laser turrets and people will die like lambs to the slaughter. People won't give a second thought to the mounds of corpses around Donut because there is a Donut nearby!
If you've got a flair for the dramatic, you can always expose Donut to radiation and help him mutate into a large, sentient, hateful being. Make sure he has the ability to float and also extensive eyebeams. Why Donut? you ask. Well, I don't know! You come up with something better, punk.
Donut has but one natural predator, the Washington, DC Police Service. Most Evil Geniuses agree that the most effective way to deal with these is through the use of a bribe.