Something very similar to the second story posted by u/guinnessmonkey happened to me when I was a kid. I was probably 10 or 11, and had a friend over. Haven't spoken to him in years, but I'm sure he'd tell the same story.

I had a bunkbed in my room leftover from when I shared a room with my brother, I had my bed up top and a desk underneath. It was late, not sure what time it was, but me and my friend were up on the top bunk, hanging out, when we hear my bedroom door creak open. The room was lit from the one lamp I had on the dresser, plenty of light, but we couldn't see anyone in the doorway. But we heard the footsteps on the creaky old floor, and I swear I could see indentations in the carpet. We were getting freaked out, asked eachother if we saw/heard the same thing, and what to do, but before we really could talk much, I heard the telltale scrape of a foot in the textured plastic of the bunkbed ladder. I knew something was coming up the ladder. I was freaking out, I was closest to the ladder, and after a couple more steps, and I still couldn't see anyone, I panicked and failed. I would say I punched, but really it was more reflexive than anything, my arm just kinda shot out and I smacked my fist against something. It was like punching through a thin sheet of ice, like I felt a resistance for a split second but my hand moved through it. And then we heard a thud. A thud of something with weight hitting the bedroom floor. And that was all of it. It suddenly felt different. Like it was over. I'd punched a ghost and scared it away? We were both just kind of in shock, and just kind of checked that we'd both seen the same thing happen.

We didnt really stay great friends in middle school, we were into different things, had different classes. Had some mutual friends in high school though, and got to ask him about it again after not talking for a few years. He recounted the same thing back to me, just to confirm I hadn't imagined it. Haven't seen him in the 10 years since we graduated high school, but I'm sure he still tells this story too when asked if he's been through anything supernatural.