The unified modeling of iron-based high-temperature superconductors has been complicated by different phenomenologies in the iron-pnictides and iron-chalcogenides. Here we use x-ray diffraction and angle-resolved photoemission spectroscopy to investigate the lattice and electronic properties of the Pr4Fe2As2Te0.88O4 (Tc=25 K) superconductor. The crystal structure undergoes a high-temperature (Ts=250 K) orthorhombic transition with no apparent magnetic transition. Further, we find the Fermi surface to consist of zone-corner electron pockets only. In addition to superconductivity, a second electronic instability -- evidenced by a spectroscopic gap below Tg≈2×Tc -- is found. Both, the electronic structure and the sequence of transitions, resemble what has been reported in monolayer and bulk FeSe. Our results thus provide a direct link between the iron-pnictide and iron-chalcogenide families of superconductors.