I once was sitting in the twins room feeding a baby in the night when my other twin woke up and started crawling towards me in his cot. For one moment of sheer terror he was not my boy but the dead baby in the move Trainspotting who crawls on the ceiling towards Ewan McGregor when he is going cold turkey off heroin. I actually backed away from him and tried to protect the baby in my arms before I realised who it was