Bowser made his first appearance in Super Mario Bros. for the Nintendo Entertainment system. Bowser is a giant firebreathing turtle who threatens the peaceful Mushroom Kingdom and is the nemesis of the main character, Mario. The scales, claws and horns make him almost dragon-like, but the spiked shell reminds us that he is a turtle-type creature. The spiked bracelets were added to make him seem more of a threatening villain.
In the Super Smash Bros. series of games, Bowser has the ability to transform into a more monstrous version called Giga Bowser. His horns become larger and more curved, the spikes on his shell become more pronounced, and his tail grows spikes, much like a stegosaurus(shown below).
There also exists a giant turtle monster known as Gamera, who has had a series of movies in Japan. This monster, who made its debut in 1965("Gamera"), may have inspired the creation of Bowser.
"Gamera -." Wikipedia, the free encyclopedia. Web. 17 Nov. 2009. [http://en.wikipedia.org/wiki/Gamera].