Made time for this. Kevin Conroy was one of my favorite influences.
The comic is a reference to the episode Beware the Gray Ghost, in which Batman needs the help of an actor he admired as a child to solve a crime.
Batman: “As a kid, I used to watch you with my father. The Gray Ghost was my hero.“
As some folks on tumblr have pointed out, Simon Trent (Gray Ghost) was voiced by Adam West.