Dream About Dead People Floating In Pool

I guess a friend had invited me to a public pool. It was dark outside. I jumped in and at first it was all good but then I swam deeper into the pool and noticed that dead people who were tied down to the bottom by a string or rope were floating just below the surface. As I panic and try to get back to the top I feel a string wrap my hand . And I pull away only to be cut open by the rope wrapped around my hand . But I make it to the top where my friends are oblivious to the situation and are happily playing in the water. The water is smooth and then starts to flow more like a river in front of me. Then I wake up