Free Cloud Riders by Don Hurst

system.
    Reshape flash-changed into different sunlit configurations of animals, plants, bugs, tools and several household appliances. Will searched the sky around him, perhaps trying to spot the Horrid Ice Castle where Reshape said his sister could be found. Isno stayed hunched down watching as they passed other clouds, his small cloud comfortable as a soft pillow.
    "Master," a friendly female voice came into Paul's consciousness.
    Paul jerked his head around to see who owned the sultry voice. “Who are you calling master?"
    "I didn't say anything, mate, don't you know,” Will said. “I'm not into, like, calling anyone master."
    "Cat master?” Isno asked.
    "I heard a voice, Will. Didn't you hear it? Calling me, master,” Paul explained apologetically.
    "Master, you ride on my back."
    Paul looked down at the fluffy white of his unicorn's back, then up to its horn. “You mean, you can talk?"
    "You are so funny, Master. I speak and you ask if I can talk."
    "You're talking to the voice in your head, mate?” Will said. “Get a hold, I'm thinking."
    "It's my unicorn cloud ride. I guess you can't hear her."
    "Clouds talk? You're pulling me."
    Reshape flash-changed into a hyena and made hysterical laughing sounds.
    Paul stared at Reshape. “What do you find so funny, Shape Loser?"
    "Reshape.” He stopped laughing the second he became an elephant-sized red mosquito. “Call me Reshape,” he said without a trace of emotion.
    "Maybe you need to suck some blood out of me, huh, you big bully?” Paul felt like a child testing a parent to see how much he could get away with, but kind of wished he hadn't put a voice to his cheeky thoughts. “You're big enough to suck the blood out of a dinosaur."
    "Yeah,” Will said, wide-eyed.
    Isno sank deeper into his cloud pillow. He buried his head between his front paws.
    Reshape became a pair of red and yellow underpants. He made a noise resembling the blowing of one's nose rather vigorously.
    "Master?"
    "I'm sorry. Reshape and I were talking,” Paul said to his unicorn.
    "Master. Aren't you going to ask me my name?"
    Noticing Isno's lack of attention and the fact Will didn't hear his unicorn gave Paul the realization his mount used thought-transfers to speak. “You have a name?” he asked aloud.
    " Oh, Master. You are so funny. Would I ask if I did not possess a name?"
    "Maybe, if I imagined it to be like that,” Paul said. “You have a name and you aren't giving it to me. Why?"
    " Master, I can do nothing without your wishes. I remain unable to give you my name unless you ask me for it."
    "I wish you to not pay any attention to that rule and speak when you need to speak."
    "I am full of joy!"
    "So, what's your name?"
    "Silk."
    "Silk, I'm glad to meet you."
    "Thank you, Master. You give me joy and the strength to maintain shape despite the winds."
    "What winds?"
    "The winds your imagination hold away from you."
    "Guess I should have mentioned that,” Reshape said, now a red-breasted robin the size of a hippopotamus. “The breezes up here are kind of deceptively active in tricky ways."
    Paul wondered if Reshape thought he talked to a complete idiot. “Apparently about as active as you find convenient?"
    "Ah, there is my worm. I have no control over the weather, clouds and even you at times,” Reshape the oversized robin confessed. “Small limitations, I assure you, when compared to all I can do."
    "Human sister?” Isno said with a purr. “No now lose?"
    "Yeah,” Will said. “Holly?"
    Paul took a deep breath. Some kind of protector he turned out to be. His cat had to tell him why he rode on Silk to begin with—dumb of him, and disloyal. “Yeah, Isno. Silk, go toward Horrid Ice Castle. Hurry."
    "Good I?” Isno purred.
    "Good you,” Paul assured.
    "Master, do you want the name of the cloud puff Isno Gravity rides upon?"
    "Yes, Silk. Does Isno's cloud puff have a name?"
    "Master is so funny. Cloud puff is named Huff. It is no relation to me."
    "Isno's cloud puff is named