The missing corpse

Last year my grandfather died from old age and we decided to go say our last goodbyes at the nearest church. We prayed for his soul to be guided to the light and read some Bible verses about life after death. The air smelled rancid and rotten.
But as we all heard a sound of someone screaming outside the pastor stopped talking, and as we turned around he was gone and the coffin was shaking. We opened it up and there lied the pastor frozen in fear and unable to talk.
Then I exclaimed, "Wait, if the pastor was in here then who was talking to us?"
And then there stood my grandpa's body, turning his head with the cracking of bones with a twisted evil smile and wide open eyes. He whimpered, "Join me in resurrection."