Yes, some of these small dogs can be downright vicious.
If you got 30+ of these evil devil dogs attaching your throat, you would probably sustain a few nips & cuts before you are able to coax them off with a few doggy treats,
To be fair on this breed though, you don't hear many stories (if any) of wild packs of Chihuahuas prowling around neighborhoods, stalking and mauling innocent venerable children to death.
You do occasionally read the same scenario happening with these 'bred to kill' dogs though.