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In multi-particle Diffusion Limited Aggregation (DLA) a sea of particlesÌýperform independent random walks until they run into the aggregate and areÌýabsorbed. In dimension 1, the rate of growth of the aggregate depends on $\lambda$, the density of the particles. Kesten and Sidoravicius proved thatÌýwhen $\lambda < 1$ the aggregate grows like $t^{1/2}$. They furthermoreÌýpredicted linear growth when $\lambda >1$ (subsequently confirmed) and $t^{2/3}$Ìýgrowth at the critical density $\lambda = 1$. We address the critical case,Ìýconfirming the $t^{2/3}$ rate of growth and show that aggregate has a scalingÌýlimit whose derivative is a self-similar diffusion process. Surprisingly,Ìýthis contradicts conjectures on the speed in the mildly supercritical regimeÌýwhen $\lambda = 1+ \epsilon$.