Hi. I often hear or read fans saying that Sludge's alternate mode doesnt exist... I know that his design was based on a term in paleonthology that is obsolete now, but that doesnt mean the dinosaur he disguises as didnt exist. Sludge in G1 was supposed to be a Brontosaurus, right? Well, the term is obsolete now as i said, but the dinosaur got a new name, and it is the Apatosaurus. And although Sludge's alt mode is not completely accurate to the dinosaur, as he resembles more those dinosaurs in The Flinstones xD, well, he certainly resembles what he supposedly is. So I guess fans are just a bit confused. Its simply that the dinosaur is no longer called Brontosaurus, but it is still part of the known species, with other name. Its not that it was discovered the Brontosaurus didnt exist as an species, it just needed some updating in terminology, anatomy and the like. Its like what happened to that tiny dinosaur previously known as Hesperosuchas. It got a name change or sumthin because its like it never existed now... Maybe in future appearances of the character, the designers should investigate a bit to update his alt mode, although the resulting changes surely wouldnt be really drastic. Just a thought.