  We discuss a novel cold dark matter candidate which is formed from the
ordinary quarks during the QCD phase transition when the axion domain wall
undergoes an unchecked collapse due to the tension in the wall. If a large
number of quarks is trapped inside the bulk of a closed axion domain wall, the
collapse stops due to the internal Fermi pressure. In this case the system in
the bulk, may reach the critical density when it undergoes a phase transition
to a color superconducting phase with the ground state being the quark
condensate, similar to BCS theory. If this happens, the new state of matter
representing the diquark condensate with a large baryon number B > 10^{20}
becomes a stable soliton-like configuration. Consequently, it may serve as a
novel cold dark matter candidate.
