Summary.A new approach is provided to the super-Brownian motion X with a single point-catalyst 8c as branching rate. We start from a superprocess U with l -stable subordinator. We constant branching rate and spatial motion given by the prove that the occupation density measure A c of X at the catalyst c is distributed as the total occupation time measure of U. Furthermore, we show that Xt is determined from A c by an explicit representation formula. Heuristically, a mass A~ of "particles" leaves the catalyst at time s and then evolves according to Itr's Brownian excursion measure. As a consequence of our representation formula, the density field x of X satisfies the heat equation outside of c, with a noisy boundary condition at c given by the singularly continuous random measure A c. In particular, x is W~ outside the catalyst. We also provide a new derivation of the singularity of the measure A c.