Various models are examined, which could give rise to point-like gamma-ray sources, at the present time indistinguishable, experimentally, from true point sources. These models involve energetic processes associated with interstellar clouds, e.g. supernova-cloud interactions, neutron star accretion inside interstellar clouds, cloud collisions, etc. The dynamical evolution of such systems is discussed and physical processes are described in a mathematical framework which can be solved. Statistical arguments are presented, where possible, on the likelihood that the scenarios may actually occur in our Galaxy. The visibility of the systems at other wavelengths, e.g. infrared, X-ray, radio etc., and further consequences, e.g. gamma-ray line emission, special radio emission line features, absorption features etc. are also discussed. Finally, a limited attempt at identification of some ‘gamma-ray objects’ is made based on the theoretical predictions.