Story: Cowbell TFs Girlfriend into Muscular Cow (Patreon)

You and your girlfriend were staying in an Airbnb. It was a guesthouse on a farm. You two were about to fuck when she saw a cowbell sitting on a shelf. She puts it on as a joke. "You want to do cowgirl?" she says with a wink.

Then her face contorted into an expression of pure fear. "I feel like shit," she grunts through clenched teeth.

You noticed her arms. They were flexing. And then you noticed they were growing. Her biceps were huge. You could see her veins growing and popping out. The rest of her body was growing too. She looked like a fucking body builder. 

"Oh my god!" she screams. Milk starts leaking out of her growing tits. "WHAT THE FUCK IS HAPPENING TO ME?!" she yells. Her voice has dropped several octaves.

"Oh no... ughHHHHH. My face..." she grunts. Her nostrils flared wider and wider. Her nose was turning pink and moist. Her face begins to stretch outwards. "MOOOOOOOOOOOOOO!" she bellows. She covers her mouth, or rather her snout, with her hand. She can't believe that sound came from her.

"It's the fucking cowbell. Fucking get it off of me!" she screams in a panic.

You fumble with the clasp but something seems wrong. It's like it fused together. She grabs at the necklace with her beefy arms and pulls with all her strength but it's no use. What ever magic was transforming her was certainly preventing her from taking it off.

You two don't know what to do. You just hug her as she grows into a massive cow beast. Eventually the changes slow down and stop.

After sitting in silence for awhile she says, "I know this sounds crazy but... do you still want to fuck? I'm super horny for some reason."