Spinosaurus and Baryonyx.

Because so many people recognize the former, but we know so very little about that entire family of dinosaurs, and currently it might be one of the easier ways to get paleontologists to argue amongst each other.

For example: the graphic in the post shows Spinosaurus standing on two legs. It was probably mostly quadrapedal, standing on all fours.

It has a huge, paddle like tail, but apparently didnt have the muscles to use it like a croc or gator does.

The entire family has denser bones suggesting an aquatic life, but most of the spinosaurids have those huge back spines which dont seem to serve a known purpose and the spinal bones have room for air sacs which runs counter to the whole aquatic thing.