Ultimate Swampfire

Ultimate Swampfire  is the evolved form of Swampfire. His first appearance was in The Final Battle: Part 2, making it Ben's first ultimate transformation, a reference to Ben's transformation to regular Swampfire in Ben 10: Alien Force, being his first transformation when he puts on the Ultimatrix. He appears in Ultimate Alien, as one of Ben's new aliens.

Appearance
After the induced evolution, Swampfire now appears as humanoid tree with three blue gooey shells containing an organic, blue-colored napalm kerosene gel-like solution (as confirmed by Dwayne McDuffie), that Ultimate Swampfire shoots out and ignite blue-colored flames that are nearly three times as hot as regular Swampfire's flames. He is the same size as original Swampfire. He has many of the same abilities. He also has the same feet as Swampfire. He now has a blue Heatblast-like face inside a blue bubble. His body is composed of petrified wood.

Abilities
His pyrokinetic and chlorokinetic abilities are greatly increased, and he can still regenerate body parts. His speed is also the same as his original form but he makes up for it with his lethal fire bombs that have knocked even Vilgax out cold. Ultimate Swampfire shoots blue flames while Swampfire shoots ordinary-colored fire, these blue flames could arguably be hotter and more powerful, as 'blue' flames are hotter in real-life. He also shoots a huge pyrokinetic beam when he combines his hands together. He also posseses super strength. He probably has the same plant abilities as Swampfire, and is shown to be able to generate a vine from his body to change forms. (By touching the Ultimatrix symbol on his chest.) His body is now difficult to torn out as he is made of wood now and wood is stronger than plants

Alien Force
The Final Battle: Part 2

Trivia

 * Ultimate Swampfire is in an online Ben 10 3D game called Ultimate Crisis.
 * In a beta Ben 10 action comic cover Ultimate Swampfire appeared to resemble Heatblast, being red, while the kerosene shells were yellow.

Normal Form

 * Swampfire