The busker was in his usual place with his usual instrument and usual rug at his feet with usual fluffy toy dog lying asleep. That is a stuffed toy doy, not a live one, but the passing dog on a leash did not realise this.
He barked, charged at it and stopped half a metre short, ran back, barked agian, charged and stopped short again.
A quick glance at the owner gave him not a clue what to do, so when in doubt, just bark repeatedly.
The owner decided to move on and the dog happily went with her, satisfied that he silenced and stilled that potentially agressive ball of fluff.