Due to the Muon Collider workshop taking place this week, this seminar will focus on the possible physics scenarios that such a machine might face, from the perspective of current thinking in theoretical physics. We have several indications, both experimental and theoretical, that the Tera-eV scale should be inhabited. I will summarize these at a non-expert level and give an overview of the various possibilities for beyond-the-Terascale physics, focusing on the usefulness of a high-precision multi-TeV accelerator; the muon collider.