Big Chill is a, moth-like alien whose wings and can fold up into a hooded robe, making him look like a phantom. He has a black body with blue and white spots on his arms and legs that resemble ice chunks, a light blue torso and large green eyes. He has three fingers and a thumb on each hand, and two toes on each foot and a third toe extension on his ankles to balance himself.
In Omniverse, Big Chill is much more muscular and has large eyebrows and sharper ears, both similar to Ultimate Big Chill. He has a belt on his waist similar to Four Arms', Diamondhead's, Ripjaws', Wildvine's, Eye Guy's, Gravattack's, Shocksquatch's, Kickin Hawk's and Molestache's. The Omnitrix symbol on his belt. He has bigger wings, claws and beard-like hair under his chin.
Big Chill is can breath a freezing vapor that automatically lowers the temperature within the vapors range, encasing his targets in a thick layer of ice. Big Chill can also generate freezing beams from his hands. He is also strong enough to lift a car. Big Chill's body contains a density-altering protoplasm that allows him to render himself intangible to phase though objects. He can combine his cryokinetic abilities with his intangibility to freeze objects he passes through. Because he can alter his density, Big Chill can levitate and fly to a certain extent without using his wings (although he is much faster if he flaps his wings). Big Chill is not only immune to the effects of extreme cold, but can also survive in extreme heat. As seen in Deep, he is shown to be able to survive underwater.
Big Chill sometimes has trouble phasing through certain types of energy. In Good Copy, Bad Copy, Big Chill was harmed by Brainstorm's electrical storms. His intangibility is also useless against opponents who can also turn intangible as both their intangibility cancels out and can touch each other. Big Chill's powers are consciously used, which means he can't use his powers if he is caught off guard. The only objects that have been proven to be able to touch intangible Big Chill are the netting from the Rustbucket, Vilgax's glove and other intangible things.
Big Chill is one of the most used aliens in Alien Force and Ultimate Alien, after Humungousaur and Jetray.
Dwayne McDuffie revealed that Big Chill cannot turn invisible, and when he did, it was an error.
Like Echo Echo, Big Chill had a voice change after the first season of Ben 10: Alien Force.
Big Chill is one of the three Omnitrix aliens to appear in Ben 10: Alien Swarm, alongside Humungousaur and Nanomech.
Much like Lodestar who loves to note his "attractiveness" (magnetic personality) because of his magnetic powers, Big Chill often gives puns of coldness or ice.
Big Chill's overall design is similar to Blue Beetle from the DC Universe.
Big Chill's design resembles the eyewitness description for the Mothman, a cryptic creature spotted several times in Point Pleasant, West Virginia in 1967. He also resembles him in powers since Mothman is sometimes described as a ghost.
Big Chill's hologram alternates between his robed form and unrobed form throughout Alien Force.