feeding frenzy

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

• noun A period of intense or excited feeding, as by sharks.
• noun Excited activity by a group, especially around a focal point.

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

• noun A wild, turbulent situation in which multiple sharks or other predatory fish attack a food species simultaneously in competition with each other.
• noun by extension A voracious competition among would-be purchasers, etc. for limited resources.