Stellar mass functions with massive galaxy excess in Bigfoot. In the first 11 panels, the blue lines show the SMFs of SFGs in each subgroup of Bigfoot, while the green dashed lines show the SMF of field galaxies at 3.5 < z < 4.5 (T. Wang et al. 2025), which is based on the same catalog as this work and has been renormalized to match the SMFs of Bigfoot. All of the four massive subgroups show a top-heavy SMF of SFGs compared with the renormalized field SMF and the less massive subgroups, suggesting the accelerated formation of massive galaxies in massive overdensities. The last panel shows the total SMF of massive subgroups with ﹩{\mathrm{log}}({M}_{{\rm{h}}}/{M}_{\odot })\gt 12.5﹩; the blue line and the red line show the distribution of SFGs and QGs, respectively. The orange line shows the total SMF, which is the sum of blue line and red line. The QGs, including both passive galaxies and poststarburst galaxies, are classified using an updated UVJ criterion (S. E. Cutler et al. 2024). Due to the limited number of QGs in each subgroup, we can only plot the total SMF of QGs instead of the SMF of QGs in each subgroup.