  We present an explanation of the unusual peak/dip/hump features observed in
photoemission experiments on Bi2212 at $T \ll T_c$. We argue that these
features arise from the interaction of the fermionic quasi-particles with
overdamped spin fluctuations. We show that the strong spin-fermion interaction
combined with the feedback effect on the spin damping due to superconductivity
yields a Fermi-liquid form of the fermionic spectral function for $\omega < 2
\Delta$ where $\Delta$ is the maximum value of the superconducting gap, and a
non-Fermi-liquid form for $\omega > 2 {\Delta}$. In the Fermi-liquid regime,
the spectral function $A({\bf k}_F,\omega)$ displays a quasiparticle peak at
$\omega = {\Delta}$; in the non-Fermi-liquid regime it possesses a broad
maximum (hump) at $\omega \gg {\Delta}$. In between the two regimes, the
spectral function has a dip at $\omega \sim 2 {\Delta}$. We argue that our
theory also explains the tunneling data for the superconducting density of
states.
