Anyone who has played any of the games in the Batman: Arkham series knows how much attention to detail Rocksteady poured into it.
From Batman: Arkham Asylum to Arkham Knight, there are countless secrets and Easter eggs to the Dark Knight and the wider DC universe.
Some of these secrets have become fairly well-known amongst the community in the years since their release, with the likes of Arkham Asylum's alternate ending scenes, Scarecrow's hidden lair in Batman: Arkham City, and Joker's 'Batman Smells' tune in Batman: Arkham Origins all amongst the most popular.
However, Rocksteady chiselling in as many nods to players as possible naturally left plenty of secrets in the shadows. Some of these took years to uncover, and a number of the following Batman: Arkham Easter eggs are perhaps still unknown to certain players today.
From unmarked locations, subtle cameos and interactions to easily missed moments of foreshadowing, these are some of the best secrets and events from the Batman: Arkham games.
10. Starro's Cameo - Batman: Arkham Knight
Starro the Conqueror might be better known for his tussles with Superman across the DC universe, however, he still manages to find a way into the Batman franchise via a hidden cameo in Batman: Arkham Knight's Batgirl: A Matter of Family DLC.
Players can find Starro at the Seagate Amusement Park in a hidden room between the Great White and the Ferris wheel. It's not an easy location to find, unmarked on the map and only being accessible through a single grate. The DC villain is being housed in captivity, stuck in an unbreakable tank with players only seeing the outline of the alien creature against the glass.
Nevertheless, there are still advertisements dotted around the room explaining to any visitors the identity of this strange exhibit and even referencing their fabled mind-controlling powers.