Action Comics #450

When a blow to the head leaves Johnny Nevada transformed into a sand-monster during a trip to Las Vegas, he finds himself haunted by an unexpected craving: the sound of public laughter. Now stranded in a city of neon and noise, he must navigate his new form while chasing a single, elusive joy—laughing crowds—before his strange new nature consumes him.

In "A Gremlin in the Works," Green Arrow and The Flash investigate a series of murders committed with polished black stones, leading to a shocking confession from a young boy named Davy Tenzer—though the police remain suspicious of the heroes themselves.