[neatoman]

Now don't get me wrong, I think it was a mistake to turn him into a fly from the start, I just don't understand why he was cured. I thought they were setting up some episode for season 5 but he never showed up in season 5, him getting cured is literally the last we see of him. As far as I can tell, the only reason it happened was to show that the retromutagen worked, setting up for the surprise that it didn't for Shredder. Of course, that could have been done with just about any character.