The blue fly in Buzz Attack is a very unique enemy, he has no direct attacks and is useless on his own, but give him some cannon fodder flies around him and he will use them as ammunition and fling them at you. The projectiles are very hard to block, but it is possible and you can get am achievement from it!
Check it out in the video below
[youtube]http://www.youtube.com/watch?v=8-GFIPz4xRM[/youtube]