Board Thread:General Discussion/@comment-33665275-20171120035000/@comment-24922135-20171122224836

I think it's mostly a case of the errors being allowed into the series and then the writers realise too late how horribly OP that would make them. The Way Big example was very clearly intentional since that's how the monster of the week is defeated. My belief is best explained by examining the Echo Echo item duplication error:

It's something small, that certainly wouldn't get noticed as being OP until way later. It's just something to help the scene move along a bit faster. The writers/story board artists probably didn't even consider it a power at the time. But when you actually think into it a bit more... Yeah that power could be abused and incredibly overpowered if used right.

If Big Chill kept the invisibility there would be almost no situation where using another alien would be a better option. All he'd need to do is go invisible then phase through the opponent unseen- freezing them from within and beating them instantly.