20 Awesome DC TV Easter Eggs You Probably Missed
10. Solomon Grundy (Arrow & Gotham)
Solomon Grundy, born on a Monday... You know the rest. Cyrus Gold was one of the toughest non-main villains Oliver had to face on Arrow, a Mirikuru-injected badass who came awfully close to putting the Arrow down for good. He was seemingly killed, but the door is open for his return thanks to his comic book reincarnation, Solomon Grundy - a zombie with super-strength, speed, and is near-indestructible.
Aside from the name Cyrus Gold, it's hinted at when Team Arrow are in his apartment after his death, and find the Solomon Grundy poem written down in a book. Gotham, too, has referenced Grundy, although it's much more obviously an Easter egg than anything that could suggest a zombie appearing on the show, with a street named 4th & Grundy.