  Multifrequency studies of galaxy clusters are crucial for inferring their
dynamical states and physics. Moreover, these studies allow us to investigate
cluster-embedded sources, whose evolution is affected by the physical and
dynamical condition of the cluster itself. So far, these kinds of studies have
been preferentially conducted on clusters visible from the northern hemisphere
due to the high-fidelity imaging capabilities of ground-based radio
interferometers located there. In this paper, we conducted a multifrequency
study of the poorly known galaxy cluster Abell 3718. We investigated the
unknown origin of an extended radio source with a length of $\sim$612 kpc at
943 MHz detected in images from the Evolutionary Map of the Universe (EMU) and
POlarisation Sky Survey of the Universe's Magnetism (POSSUM) surveys. We
analyzed optical and X-ray data to infer the dynamical state of the cluster
and, in particular, the merger activity. We conducted a radio spectral index
study from 943 MHz up to 9 GHz. We also evaluated the polarization properties
of the brightest cluster-embedded sources to understand if they are related to
the radio emission observed on larger scales. [Abstract truncated due to arxiv
limit! Please see the pdf version]
