A swarm of Nosferatu. These guys are vampires but are changed by hunger and insanity to be more feral, mindless (to a certain extent) and a slave to their hunger. They no longer talk, recognize any civilize thought or have any restrain. Very agile and can jump high, slightly stronger than humans and can climb up and down walls. They suck blood and even eat flesh to get as mutch of the blood as they can. They have no mental powers like more sophistocated vampires, cannot fly like them either.
Some of them used to be normal vampires who were punished by their peers for some trangression. Some of them used to be new vampires who were too moral to suck blood and locked themselves away thus turning into these beasts through starvation. And some of them were made like this on purpose to serve as shock troops and fodder for greater vampires. But they are still really dangerous, they're still vampires.
Nosferatu are always uglier than normal vampires. And they shreik and crawl a lot.