Pixifood

Any food substance that is highly pleasant to the taste as a child and tastes shockingly unpleasant once you become an adult.

Coined by Joe Posnanski, the original reference of course being Pixy Stix.

For more info, see:

http://joeposnanski.com/JoeBlog/2008/07/29/pixifoods-part-i/

Man, I used to love eating candy corn at Halloween as a kid, but now they taste like sugary ear wax -- a Pixifood if I ever had one.