Akula is Russian for shark, it is also the name given to the most modern and deadliest Soviet attack submarine. The Akula is a nuclear boat and is almost as quiet as the USNs 688, however it lacks the sophistication of weapons systems. The Akula, as with many Russian submarines has a distinctive tear-drop shaped conning tower. With the forward dive planes on the bow. When surfaced, the towed sonar array is visible at the top of the vertical stabilizer, it is a hydrodynamic pod similar to the fuel tanks at the end of an aircraft's wing.
The Russian Navy still operates the Akula class boats and, as of yet, has not sold any to other countries. However, Russian-built Kilo class diesel-electric submarines are a popular export item.

Akula, by an unfortunate coincidence (or possibly a clever gag on the part of well known Russian prankster Leonid Brezhnev), is also the Russian/former-USSR class name for the Project 941 ballistic missile submarine which has the NATO reporting name of Typhoon. The vessel known in the west as Akula, described in SkiBum5's writeup, is not the same machine, despite both being Russian nuclear-powered submarines; Russia calls that one Project 971, or Shchuka-B ("shchuka" is the Russian word for a kind of fresh water pike).

So the typhoon is really a shark, and the shark is really a pike.

This kind of thing is why some people say that military intelligence is an oxymoron.