Pumpkin Mario is one of Mario's Power-Up forms. Mario can turn into Pumpkin Mario by eating a Super Pumpkin. In this form, Mario gains a large Pumpkin around his body and looks a bit shorter.
Pumpkin Mario is able to flick fireballs at enemies, except these fireballs differ from Fire Mario's fireballs, as Fire Mario's bounce on the ground and look like spheres and Pumpkin Mario's fireballs fly forward and have a flare running behind it. It can also go through walls.
This power-up will be appearing in the upcoming New Super Mario Bros. Trick-Or-Treat as a common power-up.