Hammock camping in remote Liberty, Co. Florida last night. I'm talking remote, private land bordered by the Ochlocknee river on one side. 2600 acres, and I locked the gate behind me, I was the only person in there.
I had sat in a stand with a bow till light went away and I left the area to go get some food at a store about 7mi. away. I came back to my land, locked the gate and got ready to climb in my hammock. I'm camped up on the hill, upland pine forest with palmetto. There are hundreds of acres of river swamp to my east connected to the upland pine forest via branches and sloughs. My campsite was between two of those branches, I was very close to one to my west and about 300 yrs from one to my east.

About 9:30pm, I'm sitting in my chair sipping a beer, looking at trailcam pics when I heard a long call like noise that trailed off into a screech/scream..  It almost sounded like 2 people because the first part, transitions to the scream but it wasn't a clean break from one to the other, like the sounds overlapped for a second or so.
The closest thing I can describe is the first part sounded like a horn of some kind. Like an old cracker cow horn call that lasted about 3 seconds or so when it changed into a haunting scream like the demons in the movie Ghost, with Patrick Swazie, when they would appear and drag people to hell. This last part lasted about another 4-5 seconds. When I heard it the first time, I almost ignored it. It was such an odd, frightening sound I didn't want to acknowledge I was actually alone out in the woods with something making that sound. It was loud, when I started to process it.I estimated it was about 300 yds  to my east and it stayed there repeating every 20- 30 seconds or so. It started getting further away and it seemed to be moving east.
I heard it one or two more times very faintly and I was glad it was going away from me. I didn't hear it after 10pm.  
I've camped there a few times and spent a lot of time in those woods. I know what it wasn't. Not screech owl,  night herron, barred owls, etc...   Not hogs but some squealing on the last part was similar to a hogs squeal at times. Not a coyote den, although I heard two dens sounding off later in the night. I've never heard anything like that sound in my 53years. It made my hair stand up on my head and neck.  I loaded 2 rifles and slept w/ my .357 it was a long night.

Sounds like a puma or mountain lion man

I'm no expert on lions, they may have a range of vocalizations that I haven't heard. I have however heard them several times. My crazy neighbor had a female and when she was in heat she would "yawl " I guess  best describes it. I bumped into one face to face in the mountains and it growled at me, like a pissed of house cat. I have seen some others, having lived in lion country 25 years, but have never heard one scream as described by many people.

Did it sound like this OP?

Peacock?

Look up bobcats, Panthers and yotes. Prob one of the 3

Panther.

+1

Caught a glimpse of one crossing a road early AM in the Everglades. No desire to engage in cqb or even be in the same vicinity. It was big

Once hunting around Lake Okeechobee, while working my way back to the boat after dark, I heard the most horrific screams I've ever heard. It was as though the gates of hell had opened and the torment of thousands was upon the land.  It was a combination of roar and scream, and it made my blood run cold. Being part of the 45-70 master race offered little comfort.

It turned out to be a bunch of wild hogs.

Fox maybe?

That's my thought.  Ran into Mountain Lions camping before.

Damn OP...  You made the hair on my arms and neck stand up.

About 20 years ago, I was on our homestead property in North West Florida (Just south of Compass Lake)... Truck bed camping... With plans on shooting a spring gobbler the next morning.  I'd been doing that all my life and never experienced anything out there that I was remotely afraid of.  That night tho, I heard something that made me get in the cab, and I've yet to spend a night out there since.

It was like a Tarzan yell with a very high pitched screech at the end. It was two toned as you described... Very deep at first, then changed right at the end... and loud.  I heard it for about 20 minutes. I don't know how close it was, but it didn't seem to be moving... Then it just stopped. At least I knew it wasn't 30 feet away when it was making a racket out in the woods... After it let off, I didn't know where the hell it was and that was my breaking point!

...so there I was, a grown ass man, setting in the cab of a pick-up, trying to cover the windows with clothes and whatever I could find... Loaded shotgun in hand... Scared shitless.

And I have never been in those woods since, without thinking about that sound...  And what could have made it.

It really did creep me out.  It was not a cat, or bear... Not a yote. At least it didn't sound like any I've ever ran across.

I still hunt there...  But I gave up on solo camping in a truck bed.

I don’t know if you have porcupines there, but noise from porcupines fucking will make you think Bigfoot lives.

This is what I was going to say, Fox have some weird vocalizations.

It could have been a wood devil.

This

I vote fox as well.

Google their calls and you'll hear different examples.  The vixen scream is the one I heard before that sent chills up my spine.

Maybe it was bigfoot?

Edit. Not GD. Carry on.

I’m going with bobcats; unless there is a hobby farm in the area , then peacocks ( only in breading season) .

No on mountain lions or panthers as this occurred in Northwest Florida. No on peacocks, foxes or coyotes as I'm familiar with their weird sounds. I'm pretty sure we don't have porcupines here.  The video of the Puma's  was similar as it was a call answered by another call which would account for the overlap of the sounds. Bobcat videos I've watched don't have the same tone or screams. Each time I heard it, it lasted about 5 - 8 seconds.

I'd bet it was hogs. Sounded exactly as you described.

Hogs or bobcats.

I only slept on my lease in Glades County once by myself.  Honestly I was more concerned with having one of the local meth heads show up to rob the place while I was there since we were getting hit once a year on average.  They mostly just tore shit up because they are not very competent at much, even thievery.  I wasn't looking forward to shooting someone.  It's always people problems around here.

No on hogs, maybe on bobcats. I've been hunting there since I was a little kid in the 70's. I've heard hogs for 40 years in there and know how they get when they are riled up at each other with the base notes and high pitched squeals.  This was a sustained 5 - 8 second moan/scream and it ended much like the above Puma Conversation video with what sounded like 2 or more screams in unison.
That's why it reminded me of the scene in the movie Ghost.

I told you above. It was probably a wood devil.

Could it be a screech owl? They sound kinda like a woman screaming for life in the woods. Very creepy!

I'll need to Google wood devil.  And no on screech owl. It was at least 5x louder and way more intense.

Some folks call a sasquatch a wood devil.

Solo hammock camping....OP is braver than I

To far south for the man who slaps meat against a tree.

Anyone keep exotics around there close by?
Sika, Axis and even Fallow deer make some weird ass noises that you wouldn’t expect from them.

Not gd.

Sorry

There was some high fence escapees after hurricane Michael. Not sure if they had exotics but they had a reward for animals sign posted.

Wilma

We had Axis deer running the neighborhood. Owner said go ahead and shoot them.

We've heard them from time to time in the Ozarks.
There are foxes roaming the property. They make a surprising amount of noise to be so little.

It very well could be a Elk/Fallow/Sika/Red Stag Escapee type thing as they bugle and their bugles can be anything from a low guttural growl up into a high pitched scream

No cellular device to record this repeating sound?

Sounds like it to me.

You have mountain lions on the panhandle. They’ve made it down the state a bit and there’s talk of them breeding with the native panthers. Also the Everglades panthers have worked quite a ways north. I saw a juvenile panther last year in my yard in Citrus county and I’ve spoken to a few people that have seen them around up to Levy county.

Maybe a female skunk ape in heat looking for a mate.

One truly never knows what’s out in the darkness.

Big cat of some sort got into an arguement with another big cat.

You get jack rabbits down there? Rabbit screams scare the hell out of me.

Did it sound like this?