Two youths are alleged to have thrown a flaming bottle at a young boy during an assault in Chippenham.
The youngster suffered burns to his hand after the incident on the playing fields near Goodwood Way, in Cepen Park South.
He was playing with friends when two teenagers threw a lit plastic bottle containing an accelerant at him, it is alleged.
One of the attackers is described as white with long blond hair. He was wearing a hat, a black jumper and jeans with white trainers.
The other youth had short brown hair and was wearing jeans and a jumper.
Both are believed to be 16 or 17 years old.
Police are appealing for witnesses to the assault which happened at 1145 BST on 23 August.