Spotlight
When the Stage is used to get an Actor, that actor is placed in the Spotlight. That same actor remains in the spotlight until a different actor is placed there. Note, though, that a Stage and thus its corresponding Spotlight is scoped to the current Performance. A different performance has a completely independent Stage and Spotlight.
A stage may be used at any time to get the actor who is currently in the spotlight. Thus, it is possible to infer an actor in Performance logic without needing to use their name.
See the documentation for the Stage for more information.