Before entering the bathroom
اللَّهُمَّ إِنِّي أَعُوذُ بِكَ مِنَ الْخُبُثِ وَالْخَبَائِثِ
Allaahumma innee a'oothu bika minal-khubuthi wal-khabaa'ith.
O Allah, I seek refuge in You from evil and the evil ones (male and female).
Source: Sahih al-Bukhari 142