Woobat is a blue, spherical Pokémon, resembling a Honduran White Bat. It is covered in shaggy fur and has a large, piggish nose with a heart-shaped nostril. Two tufts of shaggy fur hide its eyes, and its mouth has a single fang in the center of its upper jaw. There are two relatively small, black wings on either side of its body.
Woobat's nose serves various purposes: It uses ultrasonic waves from its nostrils for echolocation, and it can also be used to grip walls as Woobat sleeps, which leaves heart-shaped marks on the walls of caves. A Woobat's heart-shaped mark is said to give good fortune to whoever it leaves its mark on. Woobat preys on bug Pokémon and is known to live in caves and dark forests.
Karl, a character in Zoroark: Master of Illusions, wears a baseball cap with a Woobat depicted on it. As Woobat's official reveal was four days before the movie's release in Japan, the reveal of Karl's design was the first time Woobat's existence was hinted at.
Woobat's evolutionary family has several similarities with Zubat's. All of the members of both lines are called the Bat Pokémon (excluding Swoobat), live in caves or other dark places, and have no visible eyes at their respective unevolved states; furthermore, members of both lines reach their respective fully evolved forms by friendship, and both have similar Shiny forms (with green main bodies). Also, Woobat and Zubat have somewhat similar English names, both having rhyming prefixes and bat as a suffix.
Woobat shares its category with the Zubat evolutionary family. They are all known as the Bat Pokémon.
Woobat appears to be based on the Honduran white bat (a white species of fruit bat) and a literal interpretation of a heart-nosed bat. It also bears some resemblance to a vampire bat, despite its difference in diet. The hair covering its eyes may be a reference to bad eyesight of bats. Its shiny form's pale green coloration is likely inspired by the Honduran white bat's tent-making behavior, living beneath leaves that filter sunlight to give the bats a camouflaging greenish appearance. Woobat's nose resembles a rubber stamp, befitting its signature move, Heart Stamp. Its single tooth resembles baby teeth which may allude to its status as the first stage Pokémon with low base stats.
Woobat may be a combination of woo and bat. It may also involve wool from its woolly appearance.
Koromori may be a combination of 心 kokoro (heart) or コロコロ korokoro (onomatopoeia for lightly rolling) and 蝙蝠 kōmori (bat).