A deathstack is a large unit (or 'stack') of units/armies/troops, usually encountered in strategy games, notable for its size, which is
intended to be large enough such that it cannot be successfully defended against by a unit of normal size. Note that a deathstack does not
necessarily signify a quantity-over-quality approach, but instead
significant and dense concentrations of force.
"Deathstack" can also be used as a verb, typically meaning the act of creating and/or using deathstacks.