Yeah, some real creepy stuff in streams and ponds. It's an act of faith to ever stick your hand under water and try to wrestle some critter out.

When I was a kid in southern Indiana, I spotted a big snapping turtle (not alligator, just regular, same disposition) crawling across a field heading for a big ditch. I ran home, grabbed a rope, and with my trusty dog headed off the turtle and finally managed to get a loop around its tail.
I dragged it home about 300 yards, put a big galvanized trash can on its side, and finally got the snapper backed in so I could raise the can back up. The turtle filled the bottom of the can, wedged tight. I carefully put a steel grate over the open top, then a concrete block on that.
When Dad came home from work, he asked as usual, "What did you do today?"
"Dad! I caught this HUGE turtle!"
"Really? Where is it?"
"In back. In a trash can with a grate and block on it."
Dad was amused, certain I was exaggerating.
"Let's take a look at it."
"Be careful, Dad. Don't take the grate off. Just peek in from a distance."
"Sure, sure, I'll be careful." With that he took the block off.
"Dad, don't do that! It's a BIG turtle!"
"I know. Don't worry ... "
He never finished the sentence. As he slid the grate off and peered over the top, that turtle shot its head clear up out of the trash can and its jaws snapped shut just inches from Dad's nose.
Dad leaped back while somehow managing to drop the grate accurately enough over the top that the can rocked back and forth but didn't turn over.
Ashen faced, he turned me and said, "That IS a big turtle!"