wolf pack

from The American Heritage® Dictionary of the English Language, 5th Edition.

• noun A group of people or machines that aggressively pursue something, especially a group of submarines that attack a single vessel or a convoy.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• noun Alternative form of wolfpack.

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

• noun a group of submarines operating together in attacking enemy convoys
• noun a group of wolves hunting together