  We investigate the effects of delayed interactions in a population of
``swarmalators", generalizations of phase oscillators that both synchronize in
time and swarm through space. We discover two steady collective states: a state
in which swarmalators are essentially motionless in a disk arranged in a
pseudo-crystalline order, and a boiling state in which the swarmalators again
form a disk, but now the swarmalators near the boundary perform boiling-like
convective motions. These states are reminiscent of the beating clusters seen
in photoactivated colloids and the living crystals of starfish embryos.
