Jazz trombonist Nadav Nirenberg tells the New York Post that he left his iPhone in a livery cab on New Year's Eve.
The next morning, the 27-year-old learned via email that someone was sending creepy messages to women using a dating app on the phone.
So he logged on to the service and offered the man a date - posing as a woman. He even sent a picture of a pretty girl.
When the culprit arrived at Nirenberg's Brooklyn apartment with wine, the musician jumped out brandishing a hammer.
But he also offered $20.
The thief handed him the iPhone and bolted.