The Bowler Hat Guy
The Bowler Hat Guy reveals himself as an aged and deeply bitter Goob, Lewis' roomate at the orphanage. Goob had harbored resentment toward Lewis for having been kept up all night from Lewis' inventing, which resulted in Goob being unable to stay awake during the big game, thus missing the winning catch. The resulting inner anger inside of him had kept him from making friends or finding a family, so he simply stayed in the orphanage (even after it had closed down) for 30 years.
It was after those 30 years that Goob concocted a plan to gain his revenge...by throwing eggs at the Robinson Indistries building entrence. It was then that he met DOR-15, a future invention of Lewis' that went horribly wrong. Both of them had a score to settle with Lewis, so they waited untill the right time to strike. Goob travels back in time to settle his score with young Lewis.
Many mishaps result in the movie (a continous theme is "I don't think this plan was thought out very well") which would lead us to award The Bowler Hat Guy with the prize for the most incompetent villain in history.