World's Most Dangerous Cake

I received this recipe in my hotmail inbox (how quaint) from a friend several years ago. The cake is good for something quick and easy, but you wouldn't want to make it for a momentous occasion!

4 T flour
4 T sugar
2 T cocoa
1 egg
3 T milk
3 T oil
3 T chocolate chips (optional)
Splash vanilla extract
1 large coffee cup (microwave safe)

Add dry ingredients to mug, and mix well.  Add the egg and mix thoroughly.
 Pour in the milk and oil and mix well...
Add the chocolate chips (if using) and vanilla extract, and mix again.
Put your mug in the microwave and cook for 3 minutes at 1000 watts.
The cake will rise over the top of the mug, but don't be alarmed!
Allow to cool a little, and tip out onto a plate if desired.
EAT ! (this can serve 2 if you want to feel slightly more virtuous). 

Why is it called "Wolrd's Most Dangerous Cake?" Start to finish, it only takes 5 minutes to prepare! Cake, anytime, day or night, in 5 minutes? Egads!