5. Suzhousaurus
Most dinosaurs are kinda scary because they have big teeth and claws and could swallow you whole. Suzhousaurus, on the other hand, is scary because it looks like some kind of hellish giant rat with a penis for a neck. This bizarre sloth/dinosaur hybrid was waddling (yes, waddling, these things really couldn't catch a break) around in the cretaceous period in what is now Northern China and stood at about six and a half metres tall. It does make you wonder why something like this would have evolved in the first place and, if I were a less trusting person, I would be tempted to suspect that a palaeontology student might have upset a tray of bones one day and tried to put them all back in the right place before anyone found out.