Riddler Trophy

The Riddler Trophies are small '?' shaped contraptions that are scattered throughout Arkham Island, Arkham City, and Gotham City by the Riddler for Batman and Catwoman to find and retrieve. They are small, mechanical boxes made up of gears and tiny generators that presumably power the neon green question mark-shaped light bars that project out of the box.

Arkham Origins Incident
After Batman retrieves all of the Enigma Datapacks, he finds a secret room with a prototype Riddler Trophy. Which presumably showed that Batman had gotten Enigma's interest in riddles going again, after he managed to retrieve all the Enigma Datapacks and unlocked all the GCR Towers, Enigma started to create his new identity as the Riddler, to further his pursuit of trying to prove himself to be Batman's intellectual superior.

Arkham Asylum Incident
After the Riddler hacks into Batman's communications from his hidden lair, he challenges the Batman to solve all of his Riddles and retrieve the Riddler Trophies he had scattered throughout the island. Riddler trophies are marked on the map if Batman collects the Riddler Maps, which were left by the Riddler before he left the island. After solving and retrieving all of the Riddles and Riddler Trophies respectively, Batman then uses Riddler's use of his communications system to trace his location to a local church in Gotham, which he forwards to the GCPD. While Batman listens in over his comms, the GCPD breaks into Riddler's hideout and incapacitates the Riddler.

Arkham City Incident
After criminals, political prisoners, and Batman himself, as Bruce Wayne, were locked up in a walled-off chunk of Gotham City, the Riddler did exactly what he enacted a year before; hide trophies and create riddles for Batman to find and solve. To improve on his last failed mission to best Batman, he made them vastly more hard to obtain along with about doubling the amount. The trophies were for not only Batman, but were curated for Catwoman as well. Catwoman's trophies were lit pink and Batman would be electrocuted if he attempted to touch them. Catwoman, however, could collect both Batman and her own trophies. This time, instead of Riddler Maps, disguised Riddler Thugs highlighted in green could be interrogated to see the trophy locations on the Arkham City Map.

Arkham Knight Incident
As part of the Riddler's grand scheme to finally best Batman, the Riddler scattered Trophies, Riddles, Destructables, and Riddler Bombs implanted within the brains of rioters, spread them throughout the three islands, and in major indoor locations. In addition, he captured Catwoman and used her to motivate Batman to engage in his various deathtraps designed to kill both Batman and Catwoman. Riddler made finding all he planted throughout the three islands the requirement for the right to be able to fight his mechanized suit of armor. Just as in Arkham City, Riddler's Informants were spread throughout the city, though they could only be found among rioters, except for a corrupt Riddler Informant cop hidden at the GCPD Headquarters.

Trivia

 * In Arkham Origins, the Riddler Trophies are replaced by Enigma Datapacks.
 * Riddler produced at least 884 trophies:
 * 1 in Arkham Origins.
 * 240 in Arkham Asylum.
 * 400 or 440 (with Catwoman DLC) in Arkham City.
 * 243 in Arkham Knight.


 * The Riddler Trophies are the only collectibles in the series to appear in all four of the main Arkham Games.
 * A piece of Militia dialogue heard in Arkham Knight details a militia member explaining how he attempted to take one of the Riddler Trophies as a souvenir of his time in Gotham, but couldn't due to it giving off an electric shock due to the Militia member not being Batman. This implies that Riddler designed them in mind to only be picked up by Batman and by Batman alone. This also helps to explain gameplay-wise why none of the various thugs around Gotham attempted to steal the various trophies scattered around Arkham City, and the whole of Gotham City during Arkham Knight. The one exception is Catwoman, who in Arkham City is able to pick up the green Riddler Trophies meant for Batman along with the pink trophies designed for her.
 * Finding a specific number of Riddler Trophies or finding a specific Riddler Trophy will unlock:
 * Audio Tapes
 * Arkham and Gotham City Stories in Arkham City and Arkham Knight respectively
 * Character Trophies
 * Concept Art
 * Challenge Maps
 * Final Stage of Riddler's Revenge in Arkham Knight
 * Four Riddler Hostage Rooms and the Final Stage of Enigma Conundrum (Riddler's Hideout) in Arkham City