The profanity pack was to be an addon that gave the Goo Balls rather more mischievous voices. It was intended to be available exclusively to people who pre-ordered the game before its official release date.
Unfortunately, as it became clear that the audience of the game included young children, complaints from parents led to 2D Boy abandoning plans for the profanity pack.
There was a contest for suggestions in the 2D Boy forum, but the due to the plans being dropped, no winners were announced.