Haha, just got one other than the one that's been posted.
Aparrently there's many types of ghosts, like has been mentioned. you got the 'weak' ones and the 'strong' ones, and the strong ones take the form of Pirs, and you can control them if you want to, but it's certainly not recomended. One Singh had many Pir ghosts under his control, but then for some reason he made a mistake in his Rehat, and for that small thing the Pirs turned against him. They would beat him, scare him,etc, the only place he would be safe from them was in Guru Ji's Darbar. So the Singh went to Baba Thakur Singh Ji and Baba Ji did an Ardas, then Singh then looked out side of the Darbar and Khalsa Fauja on horses,etc, went charging past and the Pirs didn't bother the Singh anymore.
Apologies for any mistakes.