Supernovae have provided some of the best constrains on w, the equation of state of Dark Energy. To fully understand the dark universe, we must also measure cosmological density fluctuations, with observables such as weak gravitational lensing and galaxy redshift surveys. Recently, many observations of the amplitude of cosmological density fluctuations - sigma_8 - have measured a lower value than we would expect in the Lambda-CDM model with Planck CMB parameters. This lower value of sigma_8 may be hinting at new physics in the dark universe, such as interacting dark matter, or modifications to gravity. In this poster, I’ll focus on placing novel constrains on sigma_8 with supernovae, which have traditionally been considered as probes of only the distance-redshift relation. Part of the dispersion in the supernova Hubble diagram is from cosmological density fluctuations, due to gravitational lensing and peculiar velocities. Instead of treating this dispersion merely as noise, I’ll focus on how we can obtain novel constrains on sigma_8 by modelling this dispersion as a signal, especially the characteristic non-Gaussianity due to gravitational lensing. I’ll demonstrate how we can begin to use supernovae to test a key prediction of LCDM: the equivalence of Newtonian and Lensing density fluctuations, instead of just measuring w.