The gigantic (Riesige) is a way of seeing people and things as calculable in advance. It is described as a striving to transform and remake them, affirming the continuous overcoming of their limits.
The concept of the gigantic belongs to Heidegger’s post-1930 philosophy and is sparsely explained. In Contributions to Philosophy, Heidegger refers to the gigantic as:
that through which the “quantitative” is transformed into its own “quality,” a kind of magnitude … grounded upon the … invariability of “calculation” and … rooted in a prolongation of subjective re-presentation unto the whole of entities. (GA65:441-42, my italics) (CHL)