A young man questioned about a stolen mobile phone told the investigating garda he "had a bullet for him", a court heard.
Alex Karaffa (20) also snatched €70 in cash from an elderly woman's hand after asking her for spare change in a Dublin city centre car park.
The case against him was adjourned at Dublin District Court after he admitted a litany of public order and theft offences.
Judge Bryan Smyth ordered a pre-sentence probation report.
Karaffa, of no fixed address, pleaded guilty to threatening, abusive and insulting behaviour, theft and other charges.
On December 2, 2018, a member of the public alerted gardai after Karaffa was seen acting in a threatening manner on Grafton Street.
Gardai found the accused trying to open the packaging on a mobile phone. He told them he had bought it but could not say where it came from.
Karaffa then threatened the investigating garda, saying he "had a bullet for him", and he would "get him and he would not forget his face", a garda sergeant said.
The accused tried to kick and lash out at gardai as he was restrained and arrested.
Separately, a 70-year-old woman was in Fleet Street car park on March 10, 2019, when the accused approached her and asked for spare change.
He then snatched €70 from her hand and fled. He was later identified on CCTV.
On September 19, 2019, Karaffa asked a man on D'Olier Street for a cigarette and when he gave him one, the accused reached into the victim's pocket and took €180 in cash. Karaffa fled, but the victim chased him and €170 was recovered.
A motorist at Temple Bar on January 18, 2019, said Karaffa opened his vehicle and stole a €1,000 iPad.
Karaffa put his hand into a tourist's handbag at Stephen Street Lower on March 10, 2019, but she pulled away and the accused was intercepted by gardai.
On March 9 last year, he was seen using drugs at Meeting House Square, Temple Bar.
Defence solicitor Tracy Horan said a psychological report was sought.