Man-Bat

Dr. Robert Kirkland "Kirk" Langstrom, aka Man-Bat, is an enemy of Batman, who made his appearance in Detective Comics #400.

By injecting himself with bat DNA, Kirkland transforms into a monstrous human-vampire bat hybrid creature.

Background
Dr. Kirk Langstrom was a genetic scientist who developed an extract intended to give humans the sonar sense of bats and decided to experiment on himself by testing the formula. In doing so, the results were horrific, as within a few seconds the doctor transformed into a horrible bat-like humanoid monster.

He confronted Batman when he attempted to steal all the chemicals needed to reverse his transformation, but his animalistic instincts overpowered his mind, making him more fierce and savage, forcing Batman to overpower him in order to give him the antidote.

Langstrom then redefined his formula, which could already give him the ability to maintain his reasoning during his transformation, controlling himself and swinging his intelligence with ferocity. For a while, he was dedicated to being a vigilante crime fighter until he met Francine, who would become his wife and with whom he had a daughter, Rebecca. However, his transformation returned and he became unable to maintain control over it, having several encounters with Batman believing that his daughter was dead and that Batman had been responsible for killing her and his wife.

Powers and abilities
During his transformation, Kirk Langstrom takes on the physiology of a bat, bearing the traits of this animal, such as huge wings, echolocation, and claws on his feet. At first, he needed the serum to transform, but now he is able to do so at will.

In his man-bat form, his immense wings give him the ability to fly, as well as his sharp claws are very strong to cut and tear flesh and muscle. He also possesses extremely acute senses along with superhuman strength and speed. He emits high-pitched sound waves and can hear the echoes they make when they bounce off nearby objects, allowing the Man-Bat to navigate perfectly in total darkness.

The only downside to his transformation is that he loses control over himself, acting out of sheer animal instinct and becoming more savage and violent.