Board Thread:Episode Discussion/@comment-27312496-20181119203627/@comment-24994749-20181120124210

So, I have been thinking:

The Dragon could create Grimm pools outside of the realm of darkness.

And those Grimm arms Salem used on Hazel seemed to come from some kind of Grimm pool, and look like the ones we see taking Qrow in the opening, and attacking Ruby.

So, what if what happened at the town is that within that tunnel there is one of those Grimm pools.