As Season 4 of Arrow continues production, executive producer Marc Guggenheim has been posting clues, hints and teasers on his Twitter feed for fans to follow. The latest is a call-back to a certain also-verdant superhero -- one that fans have been hoping would show up on the series for an amazing team-up.
Fans of DC superheroes will instantly recognize Coast City, home of Green Lantern. But if they somehow don't, this particular postcard plays on the oath of the Green Lantern Corps, creating a cheeky ad that fans can appreciate on any level.
This isn't the first time we've seen hints at the appearance of Hal Jordan -- Coast City was referenced in Season 3 of Arrow, and Ferris Air (whose CEO, Carol Ferris, is Hal's on-and-off sweetheart) made an appearance, in a sense, as the cast of The Flash tested out Barry Allen's powers in the series' pilot on a runway of a Ferris testing facility.
Whether we're actually going to see the snarky pilot in any form is still a mystery, but one thing is for sure: you can't tease this kind of possibility without fan speculation flying off the rails.
Season 4 of Arrow premieres on October 7th, 2015.