  Persistent oscillatory dynamics in non-equilibrium many-body systems is a
tantalizing manifestation of ergodicity breakdown that continues to attract
much attention. Recent works have focused on two classes of such systems:
discrete time crystals and quantum many-body scars (QMBS). While both systems
host oscillatory dynamics, its origin is expected to be fundamentally
different: discrete time crystal is a phase of matter which spontaneously
breaks the $\mathbb{Z}_2$ symmetry of the external periodic drive, while QMBS
span a subspace of non-thermalizing eigenstates forming an su(2) algebra
representation. Here we ask a basic question: is there a physical system that
allows to tune between these two dynamical phenomena? In contrast to much
previous work, we investigate the possibility of a \emph{continuous} time
crystal (CTC) in undriven, energy-conserving systems exhibiting
prethermalization. We introduce a long-range XYZ spin model and show that it
encompasses both a CTC phase as well as QMBS. We map out the dynamical phase
diagram using numerical simulations based on exact diagonalization and
time-dependent variational principle in the thermodynamic limit. We identify a
regime where QMBS and CTC order co-exist, and we discuss experimental protocols
that reveal their similarities as well as key differences.
