No Prep Time
Character Version Vegeta from The Saiyan Saga
Frist round old Lord Slug
Second round Prime Lord Slug
Third round Vegeta can go Oozaru
@nishi99: Who knows what his power level is because he is a movie character... but Goku had to use False SSJ to give him some hardcore damamge and IMO... False SSJ>>>Saiyan saga Vegeta and Turles...
but I do beleive he could beat Namek saga Vegeta... in his youg form.. not in old because he gets killed.. lol.
@SpeedForceSpider: Actually it makes more sense that he is around Frieza Second form and here's why: Looking at the wiki the movie plays out when Piccolo fights Frieza in his second form. King Kai said to Goku that Slug could be stronger than Frieza and considering when the movie takes place King Kai probably ment Frieza in his Second Form it would be otherwise weird if King Kai is refering to an character that isn't present anymore (Frieza First Form) however... Slug wasn't in his Giant Form so we don't know if King Kai was refering to his base form or Giant Form but IIRC Slug was in his base form when Kng Kai spoke to Goku.
Think of this scenario: Super Perfect Cell is defeated by Gohan and after those events an new enemy comes along and Gohan is there to safe the day, then King Kai speaks to Gohan and says to him that this new enemy is just as strong as Cell, its stupid to think King Kai is refering to Cell in his Imperfect Form of Semi-Perfect form rather than the current Cell. Either way Slug ROFLSTOMPS Saiyan Saga Vegeta.