Scarecrow Nightmare

Scarecrow Nightmares are a type of level featured in the Batman: Arkham series. They were heavily featured in Batman: Arkham Asylum, and reappeared in Batman: Arkham Knight. They are a result of Scarecrow injecting Fear Toxin into Batman or causing him to breathe it in.

Arkham Asylum
There are a total of three Scarecrow Nightmares in Arkham Asylum, but there is also a fourth downloadable one. The challenges usually start with a cutscene or non-action section. In the first two challenges, Batman must avoid Scarecrow's gaze - otherwise he will be killed - and get to through an obstacle course to reach a Bat Signal, which he must shine on Scarecrow. In the third challenge, Skeletons will begin appearing (both regular and Titan enhanced) and Batman will have to deal with these while avoiding Scarecrow. In the final part of the challenge, Batman must fight an army of Skeletons to light up three Bat Signals to defeat Scarecrow.

The fourth nightmare is featured in the downloadable pack "Scarecrow Nightmare" and features a never ending army of Skeletons who Batman must fight while Scarecrow taunts him in the background. If Batman is hit by a skeleton, the challenge ends. It was originally part of a GameStop pre-order deal, but has since been released as part of the GOTY edition. One nightmare involves Batman and Joker switching roles, with Batman being sent into Arkham Asylum, screaming to get out of this nightmare. Joker says to start a party "With a bang" and shoots Batman and a mission failed screen would be shown. But instead of restarting the level it aruptly cuts to Bruce Wayne's grave. Batman breaks out of his tombstone and then has to defeat Scarecrow and get out of the nightmare.

Arkham Knight
In the first mission in the game, the police officer you play as is influenced by Scarecrow's gas, and so you enter into a Scarecrow Nightmare where you must fight several undead Scarecrow entities. (Who are actually innocent civilians. Killing even one alters dialogue later in the game.)

Early in the game Batman is gassed by Scarecrow's special fear gas, thus the entirety of the game from this point onwards causes Batman to be stuck in a mix of reality, and Scarecrow Nightmare, with the Joker appearing often to the Dark Knight.

In the finale of the game, Scarecrow personally delivers fear toxin into Batman using his claw. The final level of the game is a Scarecrow Nightmare where the Joker takes down his rivals, before seeing what he truly fears, and then being followed by an army of Batman statues before finally being taken out by the Dark Knight himself.

The Scarecrow Nightmare DLC missions have Batman racing through the streets of Gotham three times to fight off the giant Scarecrow in order to beat back the fear toxin's influence.

Similar Events
While Scarecrow does not appear physically in Batman: Arkham City or Batman: Arkham Origins, there are several Scarecrow Nightmare themed levels in the games.

Arkham City
In order to prove his worth, Batman must enter a Scarecrow Nightmare-like challenge for Ra's al Ghul in order to get the antidote for his Titan poisoning. Additionally, the Mad Hatter forces Batman into a Scarecrow Nightmare-like scenario where he must fight an army of the Hatter's henchmen atop a clock face.

Arkham Origins
After being injected with Copperhead's poison, Batman enters a Scarecrow Nightmare-like environment where he sees numerous illusions and has to fight multiple Copperheads. Joker and Batman have flashbacks in the game which are similar themed to Scarecrow Nightmares, with Joker's even including the swirling vortex seen in the Scarecrow Nightmares in ''Arkham Asylum. Mad Hatter tricks Batman to a nightmarish version of Wonderland'', which, similarly to the original Scarecrow nightmares, was a sidescroller.

Trivia

 * A Scarecrow Nightmare also appears in Injustice: Gods Among Us, as part of the Scarecrow stage hazard. When someone is knocked into his cell, Scarecrow will inject them with his Fear Gas, causing them to enter the nightmare where giant Scarecrow will smash them through the arena.
 * During Arkham Asylum nightmares, sometimes lightning will strike down for a second and then again, between these two strikes, Batman changes into Scarecrow and slows to a walking pace.