Ultimate Humungousaur is an Ankylosaurus-like creature, being about 20 feet tall. Ultimate Humungousaur is more buff and muscular than his pre-evolved form, while having camo green skin instead of tan.

He has a dark blue, Ankylosaurus-like helmet with three spikes running down the top, which are silver. On the sides of his helmet, there are black ram horns, pointing down.

He possesses a dark blue, turtle shell with long spikes running down each side. His plated chest and torso are dark blue with five spikes on each end. His tail has a blue mace on the end of it, with silver spikes.

Ultimate Humungousaur's knuckles have silver barrels on them, which he can transform into four-barreled missile launchers at will. The outline of the barrel cannon is black and also has a black circle at the center. When not in use, his fingers now support black claws instead of human-like nails.

Ultimate Humungousaur wears the evolved Ultimatrix symbol on his chest.

Albedo as Negative Ultimate Humungousaur

In Alien Force, Negative Ultimate Humungousaur looked exactly like Ben's Ultimate Humungousaur, but he had red eyes and his Ultimatrix symbol was also red.

In Omniverse, Negative Ultimate Humungousaur has greyish-tan skin instead of green and his spikes are brownish yellow instead of silver. His skin is more detailed, having wrinkled textures like that of modern lizards, but his overall appearance is more techno-organic than in Ultimate Alien. On his limbs, there are exposed metallic plates and tubes that are barely covered and outlined in black strips of flesh. Also, the spikes on his evolved Ultimatrix symbol are now vein-like and longer, similar veins appear under the shoulder pads and the top area between the shell and the chest plate. The hourglass symbol is now crooked, being tilted around 30 to 45 degrees clockwise.

His helmet is silver with three spikes on the top, and two on the bottom and resembles a Styracosaurus more than an Ankylosaurus. The from of his helmet has a dark blue mask, which has a rhino-like horn on top of the nostrils. There are two smaller horns that run down the silver part of his helmet. His ram horns are replaced with tusk-like structures on his mask that point down, while also having a pair of tiny horns above his eye sockets. His eyes are outlined in black and are indented further into his head, being surrounded by pale red skin. His mouth consist of the beak on his mask and a more pronounced lower jaw, with has a large yellow fang on each end and four small skin-colored teeth in between. He also no longer has black lips. There is now three gill-like structures on each side of the silver part of his helmet.

His chest and torso have less plating, having a large chest piece on top, followed by a shorter chest piece and finally a smooth abdomen with a vertical line indent. The sides of both his mid-chest piece and his abdomen have a shark tooth-shaped extension that points upwards. The spike on his chest have been replaced with holes smaller, but similar to Terraspin, having four holes on the top chest plate and two on the one in the middle.

The shell on his back is larger and instead has a single row of spikes running down its center instead of two rows on the side. The silver outline of the shell fuses with the outline of two shoulder pads, which fracture at the shoulders' end. On the shoulder pads, there are three spikes that point towards the torso. There are also three lines with triangular points at the center of each that also point towards the torso. There also appears to be two small spikes on the elbow of each arm. Both the shell and shoulder pads have a metallic texture.

The mace on his tail has stubbier spikes, which have randomly place vertical lines. The area where the tail meets the mace is also thinner than in Ultimate Alien. There are also visible jugular veins on his neck which are detailed with horizontal lines.

When using the cannons, he now has exposed pale red muscles and tissue instead of green. There is also a fifth barrel that replaces the black circle at the center of the barrel cannon. Instead of black, the holes of the barrels are the same color as his eyes and the hourglass symbol on his Ultimatrix, which now has a white outline instead of silver. When not using his barrel cannon, his fingers are now sharper whilst keeping his black claws. His finger knuckles are also more wrinkled.