Those who hunt by night will tell you that the wildest, most vicious of all animals is the tiny shrew.
The shrew feeds only by the dark of night. He must eat his own body weight every few hours or stave to death. The ravenous shrew eats everything, bones, flesh, marrow… everything.
Intro from Attack of the Killer Shrews 1959
This nocturnal creature resembles an over-sized bat, with the mouth of a star-nosed mole.
The Manabat can be as small as a normal bat, but can grow to a size larger than a human.
This creature is feared by wizards and other magic users, as it feeds of it victim's mana.
It will hide at day and hunt at night, swooping down on its prey, engulfing the magic user's face with its slimy tentacles, thereby sucking the mana from the victim. Depending on the size of the Manabat it can drain only a portion of the wizard's mana, which he will regain in a few hours, whereas the largest creatures will drain the wizard's mana permanently, rendering them ineffective as magic users.It will not harm them in any other way.
Manabats behave like normal bats and breeds in same way and numbers.
They can be tamed by a master trainer to attack on command.