Trinity river Texas has some SERIOUSLY big alligator gar and some Super deep sticky mud
https://www.youtube.com/watch?v=Ci9hs_7SFvk

Whoaaaah!!! Get a load of that fish!

That fish does seem slow and lethargic -- not very healthy -- but still, I am just not sure it's a great idea for that guy to be trying to open its mouth to show us its teeth.

Those are very big teeth.

And yes, I did notice how muddy the shoreline is there. The location looks like a great play place. Or it would be. Minus the fish.

Nessie

yeah they don't really do i good job of showing it but he fought that fish for at least 20 minutes thats why its so tired and lethargic looking. Make no mistake though Alligator gar are predators and are a very muscular fish capable of bursts of tremendous speed so catch prey.

Check this out

https://www.iflscience.com/gustave-the-notorious-giant-crocodile-rumored-to-have-killed-over-300-people-60113

Ah, yes, the Great Texas Alligator Gar. They're all over the Trinity, Brazos and Red Rivers. This is not very far downstream from Dallas. In the same stretch of the Trinity, they also have these:

https://www.youtube.com/watch?v=-A5xoChBtZk

I can't find the clips right now, but somewhere there's some hilarious footage of people in bass boats on the Trinity catching Asian carp in the face when the fish spook at the sound of the boat motor and leap 6 feet into the air in front of the speeding boat. Well, I guess it's not that hilarious if you're the one meeting up with an airborne carp at 30 knots.

I routinely wade the Brazos and Red rivers, which are mostly very shallow, and often as I'm sloshing down the middle of the river in waist-deep water, something large and 2-3 feet down towards the murky bottom suddenly darts past me under water and is big enough to leave a wake on the surface, and startle the crap out of me in the process. I usually can't see the fish due to how muddy the water is and how far down the fish is, but it's probably a gar, a large catfish or a very healthy carp. I think I'm more wary of the big catfish, as they'll eat just about anything.

One bend of the Red River I was on last October had this beast lurking there some years ago, about the size of that Trinity fish or maybe just a tad larger:
https://www.kansasangler.com/4fishingnews/060304okrecordgar.html#:~:text=The%20record%2Dbreaking%20alligator%20gar,the%20Red%20River%20in%202002.

There's a story going around that two kids swimming in the Rio Grande were attacked by an alligator gar several years ago, but a lot of folks doubt the story. The kids are said to have survived, although the smallest one got a bit chewed up by those wicked-looking teeth. Again, the story seems doubtful, as there's never been an authenticated incident of a gar attacking a human in Texas. In addition, I've walked (yes, walked, not floated) about 60 miles of the Brazos River and maybe about 45 miles of the Red over the last 25 years, but have never had a gar attack. In fact, the only gar I've been able to actually see in full are the dead ones lying on the sandbars. The live ones avoid me, possibly because after a week on the river I don't smell very pleasant. Even the fish think I smell "fishy."

Here's the State of Texas weighing in on the issue: https://tpwd.texas.gov/fishboat/fish/management/alligator-gar/no-threat.phtml

I think the most scary thing about alligator gars is the huge doctor bill you end up with when you throw your back out trying to lift a 150-pound fish.

Although I've lived in Dallas just a hop, skip and a lawsuit away from the Trinity, I've never waded that river because frankly speaking, I don't feel it's all that sanitary in the immediate Dallas/Ft. Worth area. However, like a lot of rivers, it's said to be self-cleaning (all that mud and sand filters out industrial waste, apparently) and the further you get downstream from Dallas, the better the water quality gets. Still, I'll take my chances up against the gar on the Brazos because the water is so much more free of industrial solvents and dead gang members (the Trinity Greenbelt in Dallas is famous for turning up human remains on a regular basis).