Board Thread:General Discussion/@comment-6527064-20140413142231/@comment-24770490-20140425182931

Ultimates wrote: Big Chill is not a bug. Uprgrade is not a bug. Nanomech is not a bug. Stinkfly doesn't seem to be a bug.

It could be Eatle (though even he is not a 'bug') or Ball Weevil (but he is small, but bigger than a bug) or Crashopper (though he is a grasshopper)

If you want to be that specific none of them are bugs. They use the word Bug because it sounds good. Just like Diamondhead's head isn't diamond either, it's just a name.