C1677 Back-to-back

The woman called the police and said she found something wrong when she was sleeping at home because there seemed to be movement under his bed, so he turned over to the bed and looked down, and then he saw a corpse.

The corpse seemed to have been nailed to the bed of his house. Then, the corpse had already decayed. Logically speaking, it shouldn't have been able to reach the top. However