Golbats are unique creatures. They have the biggest jaw in the entire bat family. Though it looks weak its actually tremendously strong. Golbat is a vampiric bat and drink the blood of other animals to survive, so when it wants to feed on things like livestock etc it goes strait fot the source. Depending on the size of the Golbat and the victim it will wrap its jaw around the neck and peice the jugular vein and drink. Golbat are dangerous as if there are many drinking one victim they can compleatly drain them as each one can drain more than 10 ounces of blood a bite. They can gorge themselves so much they occationally are too heavy to fly. The victim usually doesnt realise its being fed from until its too late because the Golbat secreets a poison from its gums that numbs and paralyzes the animal so it can stay and gorge.
Their jaw also helps with catching food while flying. Though Golbat do not fly with their mouths open as many images of them depict, as it slows it down. When it sees some prey (insects or small birds) it flies high above it, then freefalls, opening its mouth at the last second and scooping it up, the poisons in its mouth soon stun or kill its now doomed prey.
Despite how they look they are keen flyers and can outfly many bird pokemon. However like Zubat it has near to no eye sight, even though eyes have become visible after it evolves. It uses sonar but its larger mouth in some cases help get a wider view span.

They also grow an extra toe, this helps it grip better to prey once its latched on.

hope you like it