invisible forces

it started as something of a spa day with a small group. There was a car or boat ride to get there. The staff seemed indifferent to everyone. People start vanishing. Someone i was there with was lying down with a sheet over them. I see shadow arms on the sheet around their upper body. I curiously leaned closer wondering if it was a design. the arms faded away and i was partially stepping on the sheet when i noticed there wasn't a person under it anymore and the sheet was lifted and pulled from the adjacent corner by an invisible being. I grabbed another sheet nearby to try to wrap its arms and couldn't grasp it around. Started flailing the sheet at it. It then lifted my up toward the ceiling fan, dropping me and lifting again. I called for help. an asian kid ran in and stared. then he ran off and this thing dropped me, as i was falling i saw a vague shadowy form dart out the door.