In order to protect Trish from the Hitman Team, Bucciarati and crew's second mission from the boss was to go find a key in Pompei for some kind of vehicle that should aid them later on. Following orders, Giorno, Abbacchio, and Fugo head to Pompei to retrieve the key. When they get there, Fugo notices a suspicious shadow reflecting in a mirror that happened to be placed on one of the pillars there...
I guess you could say that's 
the Stand's idiosyncrasy.
أعتقد يُمكنك القول بأنّ هذه سِمة خاصّة بالستاند
Das sind die Eigenarten
seines Stands.
Son algo así
como los hábitos de ese Stand.
Son algo así
como los hábitos de ese Stand.
C’est son tic à lui, en gros.
Credo che la si possa considerare
l'idiosincrasia di questo Stand.
Digamos que é uma mania que o Stand tem.
У него привычка 
приводить себя в порядок.