Long-term electrophysiological recording remains challenging, particularly on delicate skin, due to reliance on adhesive backings and conductive gels. Here, a class of all-dry, self-adhesive epidermal electrodes is presented by integrating low-density, octopus-like microstructures with porous subsurface architectures. This design offers key advantages, including low electrode-skin impedance, high air permeability, dynamic adhesion to prevent interfacial delamination, and mild adhesion strength for safe-and-easy removal. The electrodes enable stable, high-quality recordings over 24 h, maintaining signal integrity even under repeated skin deformation. Preclinical studies in healthy subjects demonstrate effective electrophysiological monitoring near the wrist and eye for > 24 h, highlighting potential applications in long-term, non-invasive monitoring scenarios such as neonatal intensive care unit monitoring, home healthcare, and sleep studies.