That's why there was a "Do not enter" sign on the gate. Despite sneaking in quietly, despite the view, she now knew why.
She snake had began to consume her a few minutes ago. She didn't realize it before it was too late, halfway up her body, pinning her arms against her body, making escape almost impossible.
It didn't feel real though, it should have been painful, the teeth sinking into her fur, puncturing holes in he hide and blood coming forth. But there wasn't anything but a sick feeling substance on her already consumed body, and a tight pinning feel around her hoofed legs and arms.
She called for help as the reptile continued to inch it's way up her body, the same sick feeling of what she though was saliva in the snake's body. Although the deer struggled, the snake wasn't holding back as the deer slipped inside it's hungry maw.
It was almost finished, the snake's mouth was behind her jaw, and slowly sliding forward.
She heard footsteps and called out.
They came closer and stopped right in front of the deer, she rolled onto her stomach and pleaded for help. But the boots just stood there, watching...
The head slipped over her eyes as she continued to plead. The boots still didn't move.

As the last plea for help escaped her muzzle, the snake lunched forward and her muzzle was shut, the snakes body holding it shut.
As she took in what she though was her last breath and sank into the inside of the snake, fully covered in the body, squeezing in, keeping her from doing anything but wiggle.
Slippery tendrils worked their way into her cervidae nose, and into her throat. After using up her remaining breath she started to thrash wildly. A hiss of air from the things in her nose gave relief.
Whatever it was, snake or not, was letting her breathe. A sick torture, consuming the victim and letting them live... but for how long?

"You shouldn't have trespassed.." a severely muffled voice said. "I made these snakes specially for nosy animals like yourself. You see, they do not kill you, no. Rather they release a smell that renders anyone near it paralyzed and when the effects wear off, there is no memory of what happened. After that they would have consumed half of it's victim already." the fur standing over her said.
The deer inside struggled, letting out muffled attempts for release.
"Oh, I know that you want out. But I have to decide your punishment."
She felt a paw grab her ankles and pull her across the grass, she could feel the cool ground slide across the reptiles skin from the inside.

"But for now, I'll just leave you inside there, the snake really brings out your body curves." She could feel him smile.

As the boots left the room where she was dragged the deer struggled in her prison, the slick insides rubbing across her fur, the body of the snake pulling in, creating somewhat of a vacuum. She truly was stuck.....