Phantom beasts are intelligent, and those like the Pseudo-Nightmare Beast Dragon, which possess an intellect comparable to humans, aren't difficult to approach.
You just need to impress it.
Without a doubt, the aura emanating from Russell, his ability to enter Gloomy Dreamland, and the enticing prospect of ascending to a Pseudo-Dragon, successfully impressed the Pseudo-Nightmare Beast Dragon.
Moments later.
A man and a horse could now walk side by side through the Snow Forest, and shortly after, Russell had successfully mounted the Pseudo-Nightmare Beast Dragon.
"Polly, I know you hate its scent, but it's important to Ice Cream..." Russell said apologetically in his mind.
"I understand, although I dislike it, I welcome it to join the Dream Family, as long as it helps Ice Cream," Unicorn Polly replied calmly, her sensible nature touching Russell's heart.
"Thank you, Polly. You know, in my eyes, you will always be my most important partner, irreplaceable."