Musk cats, as their name suggests, greatly resemble small cats. They typically have golden fur with orange and brown accents around the extremities of their body, such as ears, tail and feet. Atop the head are their iconic long, pointed ears which give them excellent auditory perception, a scraggly tuft of hair at the top of their forehead, and small whiskers that protrude from their muzzle. Their tail is typically very curly around the outer edge of the limb, making the strands appear as if the tail has multiple segments. Classic musk cats such as Myau are typically depicted as being quadrupeds with the capability of resting on their hind legs, however, more recent members of their race, such as Nyau from Phantasy Star Online 2, are bipedal with opposable thumbs.
It is worth noting that Nyau is also seen wearing a bottle around his neck. In Phantasy Star, Myau also had a bottle, but his was filled with an important medicine to cure his friend's unfortunate petrification from Medusa. Other musk cats seen on the planet Dezo in Phantasy Star II did not have such a necklace. The purpose of Nyau's bottle, whether for fashion or practicality, is unknown.
When a musk cat ingests a laerma nut, they undergo a sudden metamorphosis. Their fur gradually changes from a dull gold to a bright yellow, the body expands to roughly the size of a horse, and they sprout large wings, with small horns at each edge, which grant them the ability to fly. Their new body shape also grants them the strength to carry several people at once with them into the air.
Musk cats are interesting creatures in that they are just as capable as people to learn to manipulate photons in order to cast techniques. As they prepare the focus required for such a task, they tend to frizz the ends of their fur and raise their tails as they are casting. The cats are also able to learn and communicate human languages, as seen with Myau and Nyau. As said previously, they also are gifted with the ability to fly when they eat a laerma nut.
Phantasy Star Classic
The smart-mouthed musk cat, Myau, makes his first appearance early in Alis' adventure. Being unable to open his canister of alsulin in order to save his friend Odin from Medusa, the musk cat wandered until he was eventually captured and placed into Scion's black market. Alis purchases the cat from the vendor in an effort to locate his missing friend, and the two head to Medusa Cave. After successfully curing Odin from petrification, Myau happily agrees to join Alis' conquest for revenge against the evil Lassic.
Musk cats make a small appearance in the second millennium in Dezo's Skure Spacesport. The cats were brought along to the planet by their human caretakers prior to the disastrous gas leak accident. Although the gas mutated most of the other pets, the musk cats were unaffected and instead sought to adapt to their new foreign climate after being abandoned there. These cats, unlike Myau from the first millennium, are incomprehensible to a human without the assistance of a Magic Hat. If a Mogic Hat is worn instead, the creatures will suddenly become fierce and threaten to bite anyone that speaks to them.
In Phantasy Star IV, musk cats can be found in the Myst Valley cave. Old Man, the elderly leader of his group, speaks to Chaz and acknowledges that their meeting is not their first encounter. He then bestows unto them a Silver Tusk. It is unknown if this musk cat is Myau himself, a descendent of the legendary hero, or completely unrelated.