Wildlife Spotting

My mother found this creature in the yard this morning after a huge rainstorm. She showed it to me because she was saying it was a leech and living in suburban city in south louisiana, I've never seen one. When I first saw this thing it was contracted, probably from being messed with, it's belly was a pinkish orange with a stripe going down the middle. It was probably two inches long and an inch wide. It had no visible antennae or mouth at that time. It looked like a sliced plum with its thick dark skin on the outside and this strange belly. I went inside to get my phone to take a picture and when I came back it had stretched out to about six inches and had visible antenna. I'm not sure if it is a leech or slug but I've never seen a slug like this