Generic tracer, without revenant attack's specific traits.
No examples given.
Causes the calling missile actor to follow its target, similar to Doom's original Tracer, but without depending on the time to be a multiple of 4 tics, or spawning a TracerSmoke object. This codepointer uses no arguments. See Tracer for the Doom model homing missile, and HticTracer and WhirlwindSeek for Heretic implementations.