It is a crocodile that is similar in many ways to its pre-evolution. It has the same shade of tan and a pink belly, with black striping showing through constantly. It now walks on two legs rather than four. Its tail is longer, and there are spikes along the spine of Krokorok. The nostrils are more proportioned to the rest of the face than its pre-evolution, and the hind claws are now white. The claws are still three for each leg, and the teeth show even when the mouth is closed. The arms are less muscular now, presumably due to walking on only the back legs.
Krokorok's design appears to be based on both that of a Crocodile and a Tyrannosaurus Rex.
No other Pokémon shares the same type combination as Krokorok and its evolutionary relatives. As a result, they are the only Pokémon to receive STAB from the famous Earthquake-Crunch attack combination.
Krokorok was first revealed in the United States (along with many other non-released Pokémon) through pictures leaked onto Serebii.net by Japanese players who received their copies of Black and White early.