We present an overview of recent results for the classic problem of the survival
probability of an immobile target in the presence of a single mobile trap or of a
collection of uncorrelated mobile traps. The diffusion exponent of the traps is taken to
be either γ = 1, associated with normal diffusive motion, or
0 < γ < 1, corresponding to subdiffusive motion. We consider
traps that can only die upon interaction with the target and, alternatively, traps that
may die due to an additional evanescence process even before hitting the target. The
evanescence reaction is found to completely modify the survival probability of the target.
Such evanescence processes are important in systems where the addition of scavenger
molecules may result in the removal of the majority species, or ones where the mobile
traps have a finite intrinsic lifetime.