A man is fighting for life in hospital after an horrific acid attack which left him screaming in agony and pulling off his clothes in the street.
The victim is in a coma at a specialist burns unit in after being squirted with a noxious substance.
It is believed he may have been targeted with drain cleaner mixed with water after a spate of similar attacks in East London this year.
Witness Mr Uddin said: "Apparently it's the weapon of choice for the youths now.
"They are carrying acid in squeezy bottles of Lucozade.
"Now when you see the youths, you keep your head down. Local people are absolutely frightened."
The acid is a homemade mixture of a cleaning product and water which becomes "a deadly weapon", said Mr Uddin.
Mr Uddin was returning from his local mosque with a friend at around 11pm on Tuesday night when he witnessed the terrifying aftermath of the attack in Manor Park.
He said: "The lad was in excruciating pain. He took all his clothes off.
"He was screaming and running down the road. "
"He went to a newsagent and tried to get water for the burning sensation.
"Then the police and ambulance arrived.
"He looked in a bad way - we thought it might end up being a murder scene.
"He literally ripped his shirt off."
"I saw it on the floor and I came back 20 minutes later and it's disintegrated.
"It's a shocking tale."
Police said two men aged 32 were injured with a noxious liquid and taken to hospital.
One was discharged but the second remains in a critical condition.
A relative wrote online: "Let’s just pray my cousin pulls through this.
"He’s in a coma in a specialist hospital in Brighton and they’ve said its hard to say whether he’ll pull through."
It comes just days after local police and council promised a "blitz" on youth crime after a recent surge noxious liquid attacks.
Barking and Dagenham police said there have been 21 attacks involving corrosive liquids since January.
They announced a crackdown on problem areas and said they would target shops selling noxious fluids to young people.
Mr Uddin, who works in financial services, believes the perpetrators may have practised their attack the night before.
He found his neighbour's car had also been sprayed in a corrosive substance which burned through the paint so that the metal was left visible.
Police are investigating but have so far made no arrests.
A spokeswoman for the Met said: "Police were called at 22:56 on Tuesday, 5 July to First Avenue, E12 to reports that two men had been injured with a noxious liquid.
"Officers and the London Ambulance Service attended the scene.
"The men, both aged 32, were taken to an east London hospital for suspected acid burns. Both have received treatment; one is still in a critical condition.
"There have been no arrests at this stage.
"Anyone with information is requested to contact police on 101 or call Crimestoppers anonymously on 800 555 111"