The Polarimeter to UNify the Corona and Heliosphere (PUNCH) is a mission to understand the solar corona and the solar wind as a single system, by imaging them together over a very broad field of view out to 180 Solar Radii (45°) from the Sun itself, in all directions. Images from the 4 satellites making up the PUNCH constellation are stitched together to generate a complete 90° mosaic. PUNCH tracks and measures major transient structures in the solar wind, including the large CMEs that can cause space weather. Halo CMEs are CMEs heading directly toward Earth. On May 31st 2025, PUNCH tracked its first halo CME, crossing the entire distance from Sun to Earth. PUNCH lost sight of the leading edge less than 3 hours before impact with the GOES satellites. We have conducted a 2-D front edge analysis of the CME and its trajectory, building on the existing “ice-cream cone” model of the geometry. We compare the changes in the simple model geometry to the observed CME evolution, derive CME motion from the observations, and explore the limits of the model.