Higgs bison

Etymology
. From being elusive, not being found after a long search, akin to how the Higgs boson proved time-consuming to find. was chosen due to the similarity between and, and its characteristic mysteriousness, due to not being found.

Noun

 * 1)  The ancestor of the European bison, a species originating from the hybridization of the aurochs  and the steppe bison.