Golbat

“Once it strikes, it will not stop draining energy from the victim even if it gets too heavy to fly.”

— Pokémon Red

“It attacks in a stealthy manner, without warning. Its sharp fangs are used to bite and suck blood.”

— Pokémon Yellow

“However hard its victim's hide may be, it punctures with sharp fangs and gorges itself with blood.”

— Pokémon Gold