Police investigating five fires within the space of two hours in Port Talbot say they believe they were started by the same person.
A van, a jeep, a shed and wheelie bins outside two charity shops were all set alight between 0100 and 0300 BST.
Officers are appealing for information about a young male in a black hooded top seen in the area at the time.
Inspector Karl Eenmaa said there appeared to be "no apparent reason" for the spree.
A Renault Kangoo van and the wheelie bins belonging to the PDSA and Oxfam charity shops were set alight at the rear of Station Road.
A shed fire was reported at Cwmavon Road and a Suzuki jeep was set alight at Joseph Street in Velindre.
Insp Eenmaa said: "A police investigation is underway into these incidents which we are linking.
"It would appear that an individual has walked from the town centre to the Velindre area and for no apparent reason has started a number of fires."
He is described as being fairly young in appearance, wearing a black hooded top, denim jeans and white trainers.
Businesses and residents are urged to only put their bins out on collection days, not to store them close to windows and doors and if possible away from buildings altogether.
Anyone with information should contact South Wales Police on 101 or Crimestoppers anonymously on 0800 555111.