The advances in computer and information technology have resulted in the growth of attention to the field of robotics. Coping with unknown dynamic and complex environments has become one of the most challenging problems in robotics. On the other hand, biological systems offer a plethora of ideas as well as computing capabilities to deal with such problems. Therefore, in this paper an unconventional bio-inspired method for solving the Simultaneous Localization and Mapping (SLAM) problem is presented. The proposed approach is based on Cellular Automata (CA) and draws inspiration from the behaviour and the functionalities of the slime mold Physarum polycephalum in order for a fully-autonomous robot, equipped with just one sensor, i.e. omni-directional camera, to successfully explore and map an unknown environment. Several simulation experiments in indoor environments are conducted not only to evaluate the proposed method but also to indicate its effectiveness.