Jacob Jeremy Mercer, 32, (pictured) was arrested in the attempted armed robbery of Jacksonville Beach's 8 til Late store

A man who attempted to rob a store dressed in a Darth Vader costume quickly found out that the 'force' was not with him when police arrested him and took him into custody.

Jacob Jeremy Mercer, 32, was arrested in the attempted armed robbery of Jacksonville Beach's 8 til Late store on Sunday.

The Star Wars 'fan' entered the store with a gun while wearing the Darth Vader mask and demanded money while threatening the startled cashier.

But the store cashier fought back and picked up a bottle of salad dressing and flung it at the robber who turned and ran away, according to The Florida Times-Union.

Eyewitnesses said that the robber's Star Wars outfit included a helmet and replica of Vader's chest-mounted control box.

No one inside the store was harmed during the botched robbery attempt.

Police found his getaway car - described by eyewitnesses as 'a silver car with New York plates' - on South Fifth Street.

Mercer from Tonawanda, New York, was then apprehended after police went to the residence where he was staying and asked him to come outside.

Dark side: Mercer entered the store with a gun while wearing the Darth Vader mask and demanded money from a cashier

'I find your lack of faith disturbing': The store cashier fought back and picked up a bottle of salad dressing and flung it at the robber who then fled

Mercer, who was bleeding from the bridge of his nose, was identified by one of the witnesses as the robber.

Police found several handguns and ammunition in Mercer's backpack, a police report said.