Sirius was talking with James, Lily and Remus about, how to find Harry and get him back, when Sirius suddenly collapsed on the floor screaming and trashing around. Sirius felt the family magics examine him and then rip themselves from him. What was that? He felt gruesome pain like he had been put under the cruciatius curse for half an hour. The Potters and Remus laid him on the bed, so that he could recover from this.