You abruptly wake up from your equine dreams to a hard slap on your ass. "Wake up jack. It's time we get a start on the day." The old wizard announces as he starts loading his supplies behind your saddle.
You let out a loud "HeeHHAAAAWW" out of frustration from being in a powerless position. Once the old man loads up all his supplies he pats you on the neck and hoists himself into your saddle. He grabs the reins to direct you towards the mountain pass. You decide to ignore his demands and let out a bray while refusing to move.
"Boy you better get moving cause I'm not in the mood to break in a jackass" the bearded man exclaimed as he lifted his boots and roughly jabbed his spurs into your belly. You can't help but bray in pain. Not willing to give into the evil wizard so easily, you try bucking the wizard off your back. It seems the wizard has some experience in this behavior before as you can't knock him off. He pulls sharply on the reins and starts kicking you with his boots again.
You finally give in and start climbing across the mountain pass with this fat wizard and his belongings on your back. Throughout the pass you repeatedly ignore his commands either out of spite or to catch your breath along the grueling incline. The bearded wizard is clearly experienced at riding unruly animals though as he forces you to continue each and every time.
As the sun sets you finally get to the other side of the pass and eventually reach a small town. The wizard rides you directly to an Inn and leads you to a stable. After a tiring day you follow his every command as he unloads his supplies and ties your lead off before heading into the Inn. Finally able to relax you get your fill of water from the trough, start munching on some hay in the stable and let out a long stream of piss. Your nose picks up the scent of a Jenny in heat somewhere nearby. Your ears lay flat along your neck as you're reminded that the wizard turned you into a gelding. You consider your actions throughout the day and realize that if you ever want balls again you should probably start behaving like a proper pack mule.
Eventually the wizard comes back out clearly drunk with a wide grin on his face. Another man follows him into the stable who walks straight up to you and starts scratching behind your ear. You let out a soft bray as you lean your head into his hand.
"So this is him, eh? You sure he hasn't been broken in yet? He seems pretty friendly to me." the newcomer asks the old wizard. "Oh believe me he's as stubborn as they get. I'll give you a great deal for this dumb mule as I don't have the time go train him" the drunken wizard says.
You realize that you're about to be sold as nothing more than a gelding mule and start braying loudly and repeatedly. "I see what you mean now, he certainly needs some proper disciple before he'd be any use to me" the newcomer said simply. You stood there in disbelief as you watched them haggle on a price before shaking hands and exchanging gold.
The newcomer pats you on the head and says "see you in the morning Jack, we'll be getting an early start". Once your new owner has left the stables, your former owner comes up to you and whispers in your ear "Hope you enjoy your life of hard work you dumb jackass. For your sake, I recommend you behave yourself with your new owner". He slaps you on your ass one last time before striding from the stable.
You have trouble falling asleep as you realize that damned wizard was the only one who knew you were a human. Without him you know you'll be treated like a fat, gelding mule for the rest of your life.