Huntail is a light-blue, aquatic Pokémon with a serpentine body. Orange, semi-circular fins run the length of its spine, and there are two additional fins on the underside of its lower jaw. A large, fan-like fin projects from the top of its head. White spots that are surrounded by orange rings dot its body, which resemble its eyes. It attracts its prey by wagging its fish-shaped tail, which features glowing eye-spots, a single dorsal fin, and a single pectoral fin. Huntail's large mouth features sharp teeth and allows it to gulp its prey whole.
Huntail swims by wiggling its body, though it is not the strongest swimmer. Its sturdy spine and large eyes allows it to survive in the high pressures and darkness of the deep sea. According to tradition, Huntail washing ashore is a sign that something unfortunate will happen.
In JN063, Goh's Dewgong spotted a Huntail chasing after a group of Gorebyss and tried to fend it off. Huntail attacked Dewgong, Chloe, and Eevee and left them trapped in a cave, only to be attacked by Ash and Goh. After being defeated, Huntail was approached by one of the Gorebyss who'd fallen in love with it.
Huntail appears to have been based on the gulper eel, viperfish, onejaw, or moray eel. It also resembles the rarely seen oarfish, mainly because of its orange-colored crest and fins. Ultra Moon's Pokédex entry may be a reference to the Japanese and Taiwanese belief that beached rare fish (including oarfish) presage earthquakes or tsunamis.
Huntail may be a combination of hunt or 斑点 hanten (speck or fleck) and tail.