This version of Mario is... something, alright? GooGoo64's take on everyone's favorite jumping plumber sports several moves based on various power-ups and things Mario can do in the source games- he can shoot fireballs (OMAGAD NOWAY!!!111!), use a mushroom or a star to get bigger or be invincible for a set amount of time, respectively, and he can even attack by jumping into the enemy!-, though that's not to say this is a good thing, as Mario is coupled with lots of attacks that can lead to easy infinites and end a match in seconds. He can also clone himself and mount on Bowser... weirdly enough. It's a GooGoo64 character, so I think you kind of understand...
Fun fact: This version is inspired by Hanyou's (in)famous Super Mario 64 character but with more of a moveset, so I think this explains the usage of Bowser's sprites from said version.