Or should that be "command"?
Yes, say hello - or rather, 'privet' - to Chazz the German Shepherd dog, whose Russian owner has uploaded this video to YouTube, and made his four-legged friend an internet star as a result.
For, as you can see, Chazz can go from 'snarling and ferocious' to 'alert and perfectly normal', just with a word.
Whatever next - a dog who can sneeze on command?! Oh. Wait...