Weighted

Weighted refers to the way spells/items/abilities select targets. Any spell/item/ability (with the notable exception of one unique that avoids targeting the top stack) that is described as targeting a random stack(s) will prefer to target the largest stack(s) by NP instead (usually but not always the top stack(s)).

See also: http://wiki.the-reincarnation.org/index.php/Random_stack