Based on a tweet from Lee Unkrich.
It drove Jessie insane. It would drive anybody mad if that person really thought and observed the situation. She never pondered the possibilities or even noticed the circumstances when she first arrived at Bonnie's house when Andy had dropped her off among the other toys.
"Hey there," the plush unicorn once greeted her, "The name is Buttercup." His voice had a certain warmth to it, it seemed like a familiar voice to Jessie. Many of the other toys shared their salutations with the examining cowgirl, but for some reason, Buttercup's voice range through her head. She couldn't understand why. After processing his voice in her mind, she matched his snout, his hoofs, his tail to his voice.
Maybe it was his feminine decorations on his body that perplexed her. Maybe the small size of his didn't seem to fit the deep voice he had had.
But that doesn't apply for Chuckles, Jessie rejected in her thoughts.
Once day, Buzz and her had a jockey race.
"Just you an' I, space ranger!" Jessie challenged, jumping onto Bullseye.
"Last one to the wastebasket has to give back Mrs. Potatohead's eye," Buzz countered, motioning Buttercup to come to the toy astronaut's side.
"She's gonna be mad at ya Buzz!" teased the red head, lining up with her competitor.
"On your marks," announced Slinky, standing in the middle of the kitchen floor, "Get set! Go!" The two racers turned into pallid and brunette blurs. This seemed to be the fastest they have gone.
"Ha! I beat ya!" Jessie screamed, getting off of Bullseye.
"Are you OK, Buttercup?" asked Buzz, petting his mane.
"Yeah…" responded Buttercup between labored breathing, "I think…I need…to exercise…more…" Jessie laughed with the stuffed toy and turned to her steed.
"Are you OK, Bullseye?" she questioned. He gave his answer in a small nudge. Normally, a beaming smile would cross her face. But in this instance, she couldn't help the sympathetic feeling swelling in her chest. He seemed to wash it away when he licked her face, leaving her to grin and mumble her thanks.
Weeks later, after readjusting to the new setting, Jessie thought back to the previous, a question rising in her mind. As she sat on the edge of the windowsill, her posture grew more and more tense. Just didn't get it. Her thoughts had secluded her from reality, unaware of her surroundings. Not realizing Buttercup's approach, she continued to stare at the empty space before her.
"You alright, Jessie?" asked the concerned Buttercup.
"HOW?" she screamed, snapping out of her daze, "HOW DO YOU DO IT? WHY DO YOU DO IT?"
"…P-pardon me…what?" he replied, taken back by her abrupt reaction.
"I'm sorry I yelled like that," Jessie hastily apologized, tugging her braid anxiously, "It's just…how come you can talk…but Bullseye can't?"
Buttercup let out a heartwarming chuckle, leaving Jessie to relax her shoulders in relief. "Maybe it's because I'm a unicorn and we are magical, mystical beings?"
"I don't think that's it…"
"That's a good question Jessie," Buttercup comforted, "But I have a better one."
"What's that?" she asked, raising her eyebrow.
"Why is it that Goofy, a dog, can talk but Pluto can't?"