The Fear Toxin, is a powerful hallucinogenic drug that, when inhaled, makes the victim hallucinates their own worst fears becoming a reality. The toxin is nullified by adrenaline. It was famously created and used by Dr. Jonathan Crane during his time as the Scarecrow. J. Crane also used this toxin prior to being admitted to Arkham Asylum and a canister of it was later taken by August Cartwright to use for torture.
After Nora Fries shot Killer Frost with a freeze ray, Barry Allen and Oliver Queen came to help. Oliver tried to use his speed to throw a lightning bolt at Nora, but missed and knocked over a box containing the serum, causing the vials to shatter. Oliver and Barry then started hallucinating, seeing each other as Eobard Thawne and Malcolm Merlyn respectively.
- Hallucination: The serum can cause strong hallucinations that are hard to break out of, as shown when Oliver and Barry didn't realize they were fighting each other until Batwoman knocked them out.
Behind the scenes
- In the main DC Comics continuity, The Scarecrow's Fear Toxin is the toxin used by the Scarecrow to commit his crimes praying on people's fears.