Catfish Monster

The unnamed catfish monster was a regular catfish from Earth that was transformed into a hellish behemoth after being exposed to Verosika Mayday's flask of Beelzejuice which mutated it.

Appearance
The creature was previously a normal teal catfish, but after its mutation, it grew in massive size, growing legs for walking and a long prehensile tongue. Its scales turned gray with hints of pale blue, and had cyan-colored claws and eyes. Its whiskers, gills, and some speckles gave a bioluminescent white glow.

History
While enthralling the crowd at her concert, Verosika threw her flask of Beelzejuice to the crowd. It bounced on several beachgoers before landing in the shallow waters of the beach where the catfish was swimming. The fish was soaked in the drink and almost immediately, the catfish underwent its transformation.

Shortly after its mutation, the creature went on a rampage at the beach, where it killed several humans and pulled an inebriated Moxxie with its tongue into its mouth. Millie threw a Molotov cocktail at the monster, causing it to fall back into the sea. Millie then leapt at the beast and forced its mouth open where Moxxie was. However, since Moxxie was too drunk to reach her hand, Millie cut the monster's tongue off to free him. Moxxie was launched out of the fish's mouth, while Millie escaped by punching its wounded tongue, before climbing up its face. The fish threw Millie into the air and swallowed her as she fell, only for Millie to cut the fish open from the inside, killing the beast.

Trivia

 * It shares the same voice actress as Sallie May, both being voiced by Morgana Ignis.
 * Interestingly, the fact that the catfish was in the ocean implies it was able to live in salty bodies of water, whereas most catfish are freshwater fish.