Bats in dreams often reflect fear tied to the unknown -- and, at the same time, an instinct for navigating situations you can't fully see or understand yet. A bat's reliance on senses other than sight can point to trusting intuition when logic runs out. If the bat frightens you, the dream may be asking what exactly you're afraid to look at directly.
Use the malefics in your selections, just as the skillful doctor uses poisons in the correct measure. - Ptolomeus