Security guard David Peers watched CCTV cameras after noticing Carl Taylor, 42, was acting suspiciously at Tesco in Leigh at 10pm on Saturday.
Taylor put a Lego Star Wars toy worth £20 in his jacket and left without paying, Wigan And Leigh Magistrates’ Court heard yesterday.
Mr Peers chased Taylor and detained him, Steve Woodman, prosecuting, said.
Taylor threatened to stab him with a needle and took a syringe out of his coat pocket.
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Mr Woodman told the court: “The security officer Mr Peers was left somewhat traumatised by this incident.”
Taylor of Cedar Road, Westleigh, pleaded guilty to theft and common assault.
Karen Moorfield, defending, said he had been living “somewhat of a transient lifestyle”.
She said: “Mr Taylor goes into the store, he accepts he takes the toy. He’s going to sell that and he’s going to do that to raise some money for himself.
“He panics in the heat of the moment and he accepts in his guilty plea that he threatens the security guard.”
She said he did not intend to use the syringe, it did not have a needle attached and he “deeply regrets” what he did .
The court heard Taylor had 197 previous convictions, including 130 thefts.
In May, he was given a 10-week prison sentence, suspended for 12 months, for shoplifting.
Sentencing, Elaine Eccles, chairman of the bench, said: “This was a particularly nasty incident in a shop for which reason we feel that a prison sentence is the only course open to us. It is so serious that only custody is justified because you brandished a syringe to a store representative to attempt to escape from him. We have a duty to protect the public.”
The 10-week suspended sentence was activated, with Taylor jailed for a further 19 weeks for Saturday’s incident.
He also admitted breaching post-sentence supervision and was jailed for 14 days, to run concurrently.
He must pay a victim surcharge of £140.