Newfu is an evil maniac talking tofu species with eyes and a mouth. It's also what makes up Bob, and the "food and drinks" that are sold as a front at Mega Meaty Meat.
Its only goals seem to be the invasion and destruction of other worlds. This can be deduced by The Source's comments to Beast Boy when asked why he was using the Destruct-o-tron and Mega Meaty Meat (with Bob as the face of the operation) as a front for world destruction. The Source merely replied, "It is our way." This implies that not only has Newfu destroyed countless other worlds, but that there are others of its kind, repeating this process in a never-ending cycle. Thankfully, Beast Boy is able to discover (albeit, through torture/interrogation) that Newfu's weakness is, in fact, water. With this in mind and a newly acquired B-Ped, Beast Boy is able to defeat The Source and save the world, though that particular piece of Newfu is unable to answer to his crimes, as Cyborg mistakenly eats it. The species was later seen at the end of "Homecoming" with a Bob, though it's not certain whether this was the same cube of Newfu that had terrorized Beast Boy in "Employee of the Month".