Kent C. Koopa

Kent C. Koopa is a big Koopa Troopa that first appeared as an optional boss fought in Paper Mario

Biography
Kent first appears in Mario and his partners' way to Pleasant Path, demanding one hundred of coins if they want to pass, however, if you don't want to then you can choose battle him instead. Kent is very strong in battle and will use his shell to squish Mario and his partners, and it's highly recommended to use Watt as a partner to fight Kent. However, his biggest weakness aside from getting attacked in the tail is being put to sleep during the battle, which will advantage Mario and his partners to beat him in an easy way. Once he is finally defeated, he will retreat and let Mario and his partners pass to Pleasant Path.

Trivia

 * It's implied by Russ T. that Kent C. Koopa taught the Koopa Bros. how to fight.
 * Kent C. Koopa has a close resemblance to Hookbill the Koopa, a boss from Super Mario World 2: Yoshi's Island.