  We explore the properties of an 'almost' dark cloud of neutral hydrogen (HI)
using data from the Widefield ASKAP L-band Legacy All-sky Survey (WALLABY).
Until recently, WALLABY J103508-283427 (also known as H1032-2819 or LEDA
2793457) was not known to have an optical counterpart, but we have identified
an extremely faint optical counterpart in the DESI Legacy Imaging Survey Data
Release 10. We measured the mean g-band surface brightness to be $27.0\pm0.3$
mag arcsec$^{-2}$. The WALLABY data revealed the cloud to be closely associated
with the interacting group Klemola 13 (also known as HIPASS J1034-28 and the
Tol 9 group), which itself is associated with the Hydra cluster. In addition to
WALLABY J103508-283427/H1032-2819, Klemola 13 contains ten known significant
galaxies and almost half of the total HI gas is beyond the optical limits of
the galaxies. By combining the new WALLABY data with archival data from the
Australia Telescope Compact Array (ATCA), we investigate the HI distribution
and kinematics of the system. We discuss the relative role of tidal
interactions and ram pressure stripping in the formation of the cloud and the
evolution of the system. The ease of detection of this cloud and intragroup gas
is due to the sensitivity, resolution and wide field of view of WALLABY, and
showcases the potential of the full WALLABY survey to detect many more
examples.
