A man shouted "I've got acid" before squirting what is thought to be cleaning fluid in the face of a drinker outside a pub.
He leapt out of a car driving on Main Street in Dickens Heath, Solihull, after a group outside The Chalice shouted at the driver to slow down.
The victim, who managed to throw water on his face from a nearby dog bowl, was unhurt. The car drove off.
It comes after a spate of acid attacks in London over the past few weeks.
A separate man, thought to be the driver of the vehicle, has since been arrested and charged with a public order offence, West Midlands Police said. He is due before magistrates on 16 August.
A bottle containing a clear liquid was also recovered.
Officers are appealing to identify the man captured on CCTV squirting the liquid from the bottle outside the pub on Tuesday.
The victim, whose eyes were protected by glasses, did not suffer any burning sensation.
PC Dave Spencer said: "Given the recent spate of acid attacks in London this was a hugely irresponsible act and very scary for the victim.
"The attacker shouted 'I've got acid' but we believe it was actually an ammonia-based cleaning fluid."
Anyone with information is urged to contact the force.