I discuss a 3D N=4 SCFT that is constructed by gauging a global symmetry of the Gaiotto-Witten T[U(N)] theory. Supersymmetric localization allows for the exact evaluation of its sphere partition function which reveals a remarkably simple answer that can be interpreted as a giant graviton expansion. I give some credence to this interpretation in a direct holographic study of their S-fold dual. The holographic dual shows the existence of a dim_C=1 (non-compact) conformal manifold that preserves N=2 supersymmetry and a dim_C=2 conformal manifold where all susy is broken. By further holographic study we can compute at large rank, the (low lying) spectrum of primary operators, the partition functions on compact 3-manifolds and study their line operators.