Consider the catalytic super-Brownian motion X[sup ϱ] (reactant) in ℝ[sup d] , d≤3, which branching rates vary randomly in time and space and in fact are given by an ordinary super-Brownian motion ϱ (catalyst). Our main object of study is the collision local time L = L[sub [ϱ,X[sup ϱ] ]] (d(s,x) )of catalyst and reactant. It determines the covariance measure in themartingale problem for X[sup ϱ] and reflects the occurrence of “hot spots” of reactant which can be seen in simulations of X[sup ϱ] . In dimension 2, the collision local time is absolutely continuous in time, L(d(s,x) ) = ds K[sub s] (dx). At fixed time s, the collision measures K[sub s] (dx) of ϱ[sub s] and X[sub s] [sup ϱ] have carrying Hausdorff dimension 2. Spatial marginal densities of L exist, and, via self-similarity, enter in the long-term randomergodic limit of L (diffusiveness of the 2-dimensional model). We alsocompare some of our results with the case of super-Brownian motions withdeterministic time-independent catalysts. [ABSTRACT FROM AUTHOR]