Use contact.bodyA.node.physicsBody
:
-(void)didBeginContact:(SKPhysicsContact *)contact {
if (contact.contactPoint.y < 150) {
if (contact.bodyA.categoryBitMask == MYPhysicsCategoryBall) {
NSLog(@"body a is ball");
// contact.bodyA = nil;
contact.bodyA.node.physicsBody = nil;
}
if (contact.bodyB.categoryBitMask == MYPhysicsCategoryBall) {
NSLog(@"body b is a weapon");
}
}
I haven't tested it though