Gulliver effect
n. When a large target succumbs to an attack by numerous smaller adversaries.
Examples
2003
One might call it the Gulliver effect. Lemuel in Brobdingnag is tiny and represents no threat, so he can see the vast creatures about him in all their grotesquerie, and with impunity. The same intimacy in regard to the high and mighty can be achieved by fiction.
—Alan Wall, “The old man and the new order,” The Spectator, June 21, 2003
1996
Both events underscore the impact of what's come to be called the "Gulliver Effect" — when a large target, like electronic financial transfers, are attacked from many different directions at once.
—“Are Smart Cards Safe Enough for E-Commerce?,” Bank Systems + Technology, December 01, 1996
1986 (earliest)
IT used to be said of the United States that when it, as a great power, stretched its arms and yawned drowsily, other nations experienced earthquakes. Now the US is learning what it means to be on the other side of the ''Gulliver'' effect as its neighbor Mexico flings out its own arms - though more in desperate search of help than amiable lethargy.
—“Valuing Mexico,” Christian Science Monitor, June 12, 1986