Lightning and volcanoes are two of my personal favorite forces of nature. Both are capable of a lot of destruction, and are pretty unpredictable. A combination of the two would be terrifying, and spectacular. Perhaps something like this:
What is picture shows is a potentially new type of lightning, detected over the Redoubt Volcano in Alaska. The bolts you see are very small and very fast: each is only about a yard (3 feet) long and lasts only a couple milliseconds (for reference, a human eye blink lasts around 350 milliseconds). Even cooler, the lightning only occurs during the volcanic eruption. In fact, it is one of three types of volcanic lightning: these "tiny sparks", a "natural fireworks" (large, spectacular bolts), and an intermediate type, between the other two. The bigger bolts are caused when water and volcanic ash meet, causing a sudden thunderstorm. How the smaller sparks form, however, is still unknown. Now that they have been confirmed, researchers know how to look for them, and will be able to gain more data, which will in turn help us learn what causes this new volcanic lightning.
Source: National Geographic- New Lightning Type Found Over Volcano