J. Crane's hallucinogen

"Your friends were exposed to a powerful hallucinogen."

- Batwoman An unnamed hallucinogen belonged to J. Crane prior to being admitted to Arkham Asylum.

History
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.

Capabilities

 * 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.

Trivia

 * The hallucinogen and that fact that J. Crane used it is a reference to Scarecrow, who in the comics created a strong hallucinogenic toxin that could make people see their worst fears.
 * Despite belonging to Crane, it is currently unknown whether or not they created the serum.