The blackbody is one of the first topics the students face at the beginning of their studies on modern physics. The usual framework supposes that a blackbody emits radiation in a 3D space in the form of massless bosons (photons). This paper investigates the blackbody radiation in a more general context in order to discuss the physical hypotheses underlying it. After exposing in a nutshell standard calculations about blackbody radiation, this paper investigates the influence of a non-zero photon mass and of the dimensionality of space on the blackbody radiation. It also discusses the possibility of a fermion-emitting blackbody. The aim of this paper is mainly pedagogical because experimental evidence points towards a massless photon propagating in a 3D space: exploring hypothetical worlds can help better understand our world. (Contains 2 tables and 6 figures.)