A 15-month-old baby was taken to hospital after an industrial firework was deliberately set off inside a shop.
A man in a cloak and skeleton-type mask entered California Wines on Tonge Moor Road, Bolton, Greater Manchester, carrying the firework on Monday night.
He dropped it on the floor and ran out, but the firework went off, firing up to 200 rockets into the shop.
The shopkeeper kicked it into the porch and was not injured, but his baby son was taken to hospital as a precaution.
Police said the baby boy vomited due to smoke inhalation and was taken to the Royal Bolton Hospital.
Officers and firefighters were called to the shop just after 2130 BST and the firework was doused to make it safe.
It is believed to have been a Fantasia 218 and police are also keen to hear from any retailers who may have sold this firework to anyone.
Insp Tony Kenyon, Greater Manchester Police, said: "This was one of the worst incidents I have ever seen of someone abusing a lit firework and endangering lives.
"This was not a small firework. It could be described as an industrial-style firework with up to 200 repeat rounds so the risk of endangering life was very high.
"It was a very dangerous prank and resulted in a young baby having to go to hospital.
"Thankfully the injuries were not severe but it could have been tragic.
"I would appeal to anyone who has information about this incident to come forward and contact us as soon as possible so we can bring whoever did this to justice."
Anyone with information or anyone who saw a man dressed in a similar costume at about the time of the incident is asked to call police or Crime stoppers.
Story from BBC NEWS: http://news.bbc.co.uk/go/pr/fr/-/1/h...er/7071486.stm