Existing accounts of student thinking about mechanical wave propagation and superposition emphasize that students sometimes treat wave pulses as objects, saying, for example, that pulses bounce off of one another when they meet. In this paper, we present a context in which students explicitly reason about pulses as not-objects, instead describing pulses as disturbances or energy and arguing that pulses can be in the same place at the same time. Our analysis highlights that students have resources for thinking about mechanical wave pulses and that student thinking is context-dependent.