A lightcone is necessarily an orbifold. It is a Penrose space (or product of penrose spaces), alongside a designated singularity (base point) which is denoted $\mathfrak{b}$. This singularity has an effective action, denoted by $\hat{\mathfrak{b}}$, which is akin to the four-momentum.\footnote{Of, presumedly, a force-carrying quantum.} In this paper, I shall summarize the facts about lightcones, and shed some light on the dynamics of massless antiparticles.